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• Ti Launchpad

  - by raysmithequip

  Just thought I would get a couple of notes up here for reference to anyone that is interested...it is now Feb 2011 and I have not been posting here enough to remember this blog. Back in Nov 2010 I ordered the Ti launchpad msp430, it is a little target board kit replete with a mini USB cable, two very inexpensive programmable mcu's and a couple of pin headers with a couple of led's on board, a spi connector some on board jumpers and two programmable micro switches....all for less than $5.00...INCLUDING SHIPPING!!....not bad when the ardruino's are running around 20.00 for the target board, atmega328 and cable off of eBay...I wont even mention the microchip pic right now.  Naw, for $5.00 the Ti launchpad kit is about the cheapest fun around...if-uns your a geek that is... Well, the launchpad was backordered for almost two months, came like Xmas eve in fact...I had almost forgotten it!! And really, it was way late and not my idea of an Xmas present for myself.  That would of been the web expressions 4 I bought a few weeks back.  With all the holidays, I did not even look at it till last week, in fact I passed the wrapped board around at my local ham club meeting during points of personal privilege....some oh's and ahhs but mostly duhs...I actually ordered it to avoid downloading the huge code compressor studio 4 (CCS) that was supposed to be included on the cd.  No cd.  I had already downloaded IAR  another programming IDE for these little micro bugs. In my spare time I toyed with IAR and the launchpad board but after about two days of playing delete the driver with windows I decided to just download CCS 4, the code limited version, and give that a shot......CCS 4, is a good rewrite from the earlier versions, it is based on Eclipse as an IDE and includes the drivers for the msp430 target board I received in the kit.  Once installed I quickly configured the debugger for the target chip which was already plugged into the dip socket at the factory, msp430G2131 from he drop down list and clicked ok...I was in!! The CCS4 is full of bells and whistles compared to the IAR, which I would of preferred for the simplicity.  But the code compressor studio really does have it all!!..the code limited version is free, and of all things will give you java script editor box.  The whole layout in debugger mode reminds me of any modern programmer IDE...I mean sure give me Tex anytime but you simply must admire all the boxes and options included in the GUI.  It was a simple matter to check the assembly code in the flash and ram memory that came preloaded for the launchpad kit.  Assembly.  I am right now looking for my old assembly textbooks...sure I remember how to use mov and add etc but a couple of the commands are a little more than vague anymore.  Still, these little mcu's are about 50 cents each and might just work in a couple of projects I have lined up for the near future.  I may document the code here.  Luckily, I plan to write the code in c++ for the main project but if it has to be assembly, no prob.  For reference, the program that came already on the 2131 in the kit was a temperature indicator that alternately flashed red and green leds and changed the intensity of either depending on whether the temp was rising or falling...neat.  Neat enough that it might be worthwhile banging out a little GUI in windows 7 to test the new user device system calls, maybe put a temp gauge widget up on the desktop...just to keep from getting bored.  If you see some assembly code on this blog, you know I was doing something with one of the many mcu's out there.....thats all for now, more to follow...a bit later, of course.

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• More on PHP and Oracle 11gR2 Improvements to Client Result Caching

  - by christopher.jones

  Oracle 11.2 brought several improvements to Client Result Caching. CRC is way for the results of queries to be cached in the database client process for reuse.  In an Oracle OpenWorld presentation "Best Practices for Developing Performant Application" my colleague Luxi Chidambaran had a (non-PHP generated) graph for the Niles benchmark that shows a DB CPU reduction up to 600% and response times up to 22% faster when using CRC. Sometimes CRC is called the "Consistent Client Cache" because Oracle automatically invalidates the cache if table data is changed.  This makes it easy to use without needing application logic rewrites. There are a few simple database settings to turn on and tune CRC, so management is also easy. PHP OCI8 as a "client" of the database can use CRC.  The cache is per-process, so plan carefully before caching large data sets.  Tables that are candidates for caching are look-up tables where the network transfer cost dominates. CRC is really easy in 11.2 - I'll get to that in a moment.  It was also pretty easy in Oracle 11.1 but it needed some tiny application changes.  In PHP it was used like: $s = oci_parse($c, "select /*+ result_cache */ * from employees"); oci_execute($s, OCI_NO_AUTO_COMMIT); // Use OCI_DEFAULT in OCI8 <= 1.3 oci_fetch_all($s, $res); I blogged about this in the past.  The query had to include a specific hint that you wanted the results cached, and you needed to turn off auto committing during execution either with the OCI_DEFAULT flag or its new, better-named alias OCI_NO_AUTO_COMMIT.  The no-commit flag rule didn't seem reasonable to me because most people wouldn't be specific about the commit state for a query. Now in Oracle 11.2, DBAs can now nominate tables for caching, either with CREATE TABLE or ALTER TABLE.  That means you don't need the query hint anymore.  As well, the no-commit flag requirement has been lifted.  Your code can now look like: $s = oci_parse($c, "select * from employees"); oci_execute($s); oci_fetch_all($s, $res); Since your code probably already looks like this, your DBA can find the top queries in the database and simply tune the system by turning on CRC in the database and issuing an ALTER TABLE statement for candidate tables.  Voila. Another CRC improvement in Oracle 11.2 is that it works with DRCP connection pooling. There is some fine print about what is and isn't cached, check the Oracle manuals for details.  If you're using 11.1 or non-DRCP "dedicated servers" then make sure you use oci_pconnect() persistent connections.  Also in PHP don't bind strings in the query, although binding as SQLT_INT is OK.

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• Business Choices and Evony

  - by Robert May

  Recently, I’ve been playing a game called Evony, and I finally decided to quit the game and thought I should warn others who might be tempted.  I also find a lot of insight with this game as an example.  A few of the companies that I’ve worked with or worked for have been like this and they are NOT good places to be. Evony is a joke designed to milk as much money out of people as possible.  As a professional software developer who mentors teams on how to build better software, here's what I see: They obviously offshore all development and have little oversight over that offshore development, and they probably have a small team at that.  Evidenced by the poor grammar throughout the game. They're seeking to maximize revenue and pushing to do as little development as possible, which would mean a small team. They're horribly understaffed in the customer support department as evidenced by never replying to this forum and never responding to bug reports or help requests (I've had one open with no response AT ALL for over a month . . .) They have way inadequate testing, no CI, and probably no automated unit tests.  You can see this by the poor grammar throughout the game and the type of bugs that show up. They aren't following a formal development process (no Agile, Waterfall, or anything else) as evidenced by their lack of predictable release cycle and lack of visibility. I'm guessing that the internal code base is terrible, otherwise, there wouldn't be an "Age II" that had nothing more than a new visual interface and a few rule tweaks.  This is also evidenced by the itty bitty scope of bug fixes and their inability to really fix bugs. Their Architect sucks.  Really, 42k user is all you can handle on a single server?  Could you REALLY not come up with a better way to scale to handle users?  They've built isolated worlds, instead of a single continuous world. Back to milking people for money--to really progress, you have to spend money. All of this adds up to knowing, deliberate actions on the part of management.  They CHOOSE to do this (like AOL choosing to send more discs instead of improve quality). So, what can we learn? This game will never really improve, since the bosses don't care, they're only in it for the money. The game will never have good support.  Again, the owners don't care. Giving them money only perpetuates this scam (and yes, I've given them money, way too much money. :() They don't care if you quit.  There's a new sucker born every day. Don't EVER go to work for them.  I've worked both with and for people like this and the culture is NEVER good. Ah well. Technorati Tags: Evony

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• Less Can Be More In E-Commerce

  - by Michael Hylton

  Today’s consumers are inundated with product choices and vendors. Visit your favorite electronics retailer and see the vast assortment of flat panel televisions. Or the variety of detergents at the supermarket. All of this can be daunting for the average consumer who is looking for the products and services that interest them.  In a study titled “Choice is Demotivating: Can One Desire Too Much of a Good Thing”, the author, Sheena Iyengar found that participants actually reported greater subsequent satisfaction with their selections and wrote better essays when their original set of options had been limited. The same can be said for e-commerce and your website. Being able to quickly convert shoppers into buyers with effective merchandising is what makes leading businesses successful. You want to engage each individual visitor with the most-relevant content to drive higher conversions and order values while decreasing abandonment, but predicting what will resonate with each customer is difficult. In a world of choices, online merchandizing tools can help personalize, streamline, and refine what your customers view when they browse your online catalog. The key to being effective is to align your products and content as closely as possible with the customer’s needs. The goal on the home page is to promote your brand and push visitors farther into the site. The home page is often the starting point for repeat customers as well as for new visitors hoping to address their current product needs. As the customer selects different filters and narrows the choices, valuable information is being provided to the retailer about the customer’s current need—regardless of previous search behavior or what other customers with a similar demographic profile have purchased. Together with search pages, category browse pages are among the primary options available to customers as a means of finding products on your site. Once a customer reaches the product detail page, it is clear what that person desires, regardless of the segment the customer falls into. However, don’t disregard campaign-based promotions completely. A campaign targeted to all customers but featuring rule-driven promotions tied to the product can be effective. Click here to learn more about merchandizing techniques so what your customer sees if half full and not half empty.

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• Less Can Be More In E-Commerce

  - by Michael Hylton

  Today’s consumers are inundated with product choices and vendors. Visit your favorite electronics retailer and see the vast assortment of flat panel televisions. Or the variety of detergents at the supermarket. All of this can be daunting for the average consumer who is looking for the products and services that interest them.  In a study titled “Choice is Demotivating: Can One Desire Too Much of a Good Thing”, the author, Sheena Iyengar found that participants actually reported greater subsequent satisfaction with their selections and wrote better essays when their original set of options had been limited. The same can be said for e-commerce and your website. Being able to quickly convert shoppers into buyers with effective merchandising is what makes leading businesses successful. You want to engage each individual visitor with the most-relevant content to drive higher conversions and order values while decreasing abandonment, but predicting what will resonate with each customer is difficult. In a world of choices, online merchandizing tools can help personalize, streamline, and refine what your customers view when they browse your online catalog. The key to being effective is to align your products and content as closely as possible with the customer’s needs. The goal on the home page is to promote your brand and push visitors farther into the site. The home page is often the starting point for repeat customers as well as for new visitors hoping to address their current product needs. As the customer selects different filters and narrows the choices, valuable information is being provided to the retailer about the customer’s current need—regardless of previous search behavior or what other customers with a similar demographic profile have purchased. Together with search pages, category browse pages are among the primary options available to customers as a means of finding products on your site. Once a customer reaches the product detail page, it is clear what that person desires, regardless of the segment the customer falls into. However, don’t disregard campaign-based promotions completely. A campaign targeted to all customers but featuring rule-driven promotions tied to the product can be effective. Click here to learn more about merchandizing techniques so what your customer sees if half full and not half empty.

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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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• links for 2011-01-12

  - by Bob Rhubart

  WebCenter Spaces 11g PS2 Template Customization (Javier Ductor's Blog) "Recently, we have been involved in a WebCenter Spaces customization project. A customer sent us a prototype website in HTML, and we had to transform Spaces to set the same look and feel as in the prototype..." Javier Ductor (tags: oracle otn webcenter enteprise2.0) Matt Carter: Risky Business "Incorporating risk detection and mitigation capabilities into apps is becoming all the rage. There are plenty of real-life examples of cases where prevention of cyber-security threats and fraudsters might have kept governments and companies out of the news, and with more money in their accounts." (tags: oracle otn security middleware) John Brunswick: 5 Surprisingly Good Benefits of Corporate Blogs "Some may still propose that not all corporations are going to be able to provide the five benefits above and are more focused around shameless self promotion of products and services.  If that is the case, that corporation is most likely not producing something of high value." - John Brunswick (tags: oracle otn enterprise2.0 blogging) InfoQ: IT And Architecture: Inside-Out Perspectives The software industry is in disarray, costs are escalating, and quality is diminishing. Promises of newer technologies and processes and methodologies in IT are still far from materializing on any significant scale. Bruce Laidlaw and Michael Poulin - each with more than 30 years of experience compared notes on the past and present of IT and provide insights on what IT needs to make progress. (tags: ping.fm) SOA & Middleware: Canceling a running composite instance - example Useful tips from Niall Commiskey. (tags: soa middleware oracle) BPEL 11.1.1.2 Certified for Prebuilt E-Business Suite 12.1.3 SOA Integrations (Oracle E-Business Suite Technology) "A new certification was released simultaneously with the E-Business Suite 12.1.3 Maintenance Pack late last year: the use of BPEL 11g Version 11.1.1.2 with E-Business Suite 12.1.3." -- Steven Chan (tags: oracle bpel) Marc Kelderman: OSB: Deploy Service Level Agreement (SLA), aka Alert Rule "The big issue with these SLAs is the deployment. If you have dozens of services, with multiple operations, and you have a lot of environments it takes a while to create them...[But] I have a nice workaround." - Mark Kelderman  (tags: oracle otn soa osb sla) @myfear: Java EE 7 - what's coming up for 2012? First hints. "Even if the actual Java EE 6 version is still not too widespread, we already have seen the first signs of the next EE 7 version written to the sky." -- Markus "myfear" Eisele (tags: oracle otn oracleace java)

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• Setting up port forwarding for 7000 appliance VM in VirtualBox

  - by uejio

  I've been using the 7000 appliance VM for a lot of testing lately and relied on others to set up the networking for the VM for me, but finally, I decided to take the dive and do it myself.  After some experimenting, I came up with a very brief number of steps to do this all using the VirtualBox CLI instead of the GUI. First download the VM image and unpack it somewhere.  I put it in /var/tmp. Then, set your VBOX_USER_HOME to some place with lots of disk space and import the VM: export VBOX_USER_HOME=/var/tmp/MyVirtualBoxVBoxManage import /var/tmp/simulator/vbox-2011.1.0.0.1.1.8/Sun\ ZFS\ Storage\ 7000.ovf (go get a cup of tea...) Then, set up port forwarding of the VM appliance BUI and shell:First set up port as NAT:VBoxManage modifyvm Sun_ZFS_Storage_7000 --nic1 nat Then set up rules for port forwarding (pick some unused port numbers):VBoxManage modifyvm Sun_ZFS_Storage_7000 --natpf1 "guestssh,tcp,,4622,,22"VBoxManage modifyvm Sun_ZFS_Storage_7000 --natpf1 "guestbui,tcp,,46215,,215" Verify the settings using:VBoxManage showvminfo Sun_ZFS_Storage_7000 | grep -i nic Start the appliance:$ VBoxHeadless --startvm Sun_ZFS_Storage_7000 & Connect to it using your favorite RDP client.  I use a Sun Ray, so I use the Sun Ray Windows Connector client: $ /opt/SUNWuttsc/bin/uttsc -g 800x600 -P <portnumber> <your-hostname> & The portnumber is displayed in the output of the --startvm command.(This did not work after I updated to VirtualBox 4.1.12, so maybe at this point, you need to use the VirtualBox GUI.) It takes a while to first bring up the VM, so please be patient. The longest time is in loading the smf service descriptions, but fortunately, that only needs to be done the first time the VM boots.  There is also a delay in just booting the appliance, so give it some time. Be sure to set the NIC rule on only one port and not all ports otherwise there will be a conflict in ports and it won't work. After going through the initial configuration screen, you can connect to it using ssh or your browser: ssh -p 45022 root@<your-host-name> https://<your-host-name>:45215 BTW, for the initial configuration, I only had to set the hostname and password.  The rest of the defaults were set by VirtualBox and seemed to work fine.

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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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• Mastering snow and Java development at jDays in Gothenburg

  - by JavaCecilia

  Last weekend, I took the train from Stockholm to Gothenburg to attend and present at the new Java developer conference jDays. It was professionally arranged in the Swedish exhibition hall close to the amusement park Liseberg and we got a great deal out of the top-level presenters and hallway discussions. Understanding and Improving Your Java Process Our main purpose was to spread information on JVM and our monitoring tools for Java processes, so I held a crash course in the most important terms and concepts if you want to affect the performance of your Java process. From the beginning - the JVM specification to interpretation of heap usage graphs. For correct analysis, you also need to understand something about process memory - you need space for the Java heap (-Xms for initial size and -Xmx for max heap size), but the process memory also contain the thread stacks (to a size of -Xss), JVM internal data structures used for keeping track of Java objects on the heap, method compilation/optimization, native libraries, etc. If you get long pause times, make sure to monitor your application, see the allocation rate and frequency of pause times.My colleague Klara Ward then held a presentation on the Java Mission Control product, the profiling and diagnostics tools suite for HotSpot, coming soon. The room was packed and very appreciated, Klara demonstrated four different scenarios, e.g. how to diagnose and fix latencies due to lock contention for logging.My German colleague, OpenJDK ambassador Dalibor Topic travelled to Sweden to do the second keynote on "Make the Future Java". He let us in on the coming features and roadmaps of Java, now delivering major versions on a two-year schedule (Java 7 2011, Java 8 2013, etc). Also letting us in on where to download early versions of 8, to report problems early on. Software Development in teams Being a scout leader, I'm drilled in different team building and workshop techniques, creating strong groups - of course, I had to attend Henrik Berglund's session on building successful teams. He spoke about the importance of clear goals, autonomy and agreed processes. Thomas Sundberg ended the conference by doing live remote pair programming with Alex in Rumania and a concrete tips for people wanting to try it out (for local collaboration, remember to wash and change clothes). Memory Master Keynote The conference keynote was delivered by the Swedish memory master Mattias Ribbing, showing off by remembering the order of a deck of cards he'd seen once. He made it interactive by forcing the audience to learn a memory mastering technique of remembering ten ordered things by heart, asking us to shout out the order backwards and we made it! I desperately need this - bought the book, will get back on the subject. Continuous Delivery The most impressive presenter was Axel Fontaine on Continuous Delivery. Very well prepared slides with key images of his message and moved about the stage like a rock star. The topic is of course highly interesting, how to create an infrastructure enabling immediate feedback to developers and ability to release your product several times per day. Tomek Kaczanowski delivered a funny and useful presentation on good and bad tests, providing comic relief with poorly written tests and the useful rules of thumb how to rewrite them. To conclude, we had a great time and hope to see you at jDays next year :)

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• Writing or extending existing emacs packages: is it worth or should I move to Netbeans/Eclipse?

  - by Andrea

  I'm finishing my master degree course in CS and I've almost become addicted to Emacs. I've used it to write in C, Latex, Java, JSP,XML, CommonLisp, Ada and other languages no other editor supported, like AMPL. I'd like to improve the packages I've been using the most or create new ones, but, in practice, I find that the implementation of Emacs leaves a lot to be desired. There are a lot of poorly-featured/poorly-maintained packages with either overlapping functionalities or obscure incompatibilities, and Elisp just seems to foster the situation by lacking the common features modern lisps have. In contrast Eclipse and Netbeans are actively improved and it does seem they can be effective for non-mainstream languages. I tried Hibachi for Ada in Eclipse and it worked well, there's CUPS for Lisp in Eclipse and LambdaBeans built using NetBeans components. On the other hand those plugins seem to be less active than their Emacs' counterparts, for example Hibachi was archived last year. What's your opinion on this? Which editor should I write extension for? EDIT: To answer Larry Coleman (see comment below): I like Emacs as a user because it is efficient both for me and the computer I'm using. It's fast and the textual interface (i.e. minibuffer) allows for quick interaction. It's solid and packages are usually small and easy to manage. If I need to correct or remove something I usually just have to change a row in my .emacs or an elisp file, or delete a directory. Eclipse plugins rely on a more complicated process that screwed my Eclipse configuration a couple of times, forcing me to do a clean reinstall. Emacs works as long as I use the basic packages. If I need something more complicated the situation gets pretty hairy. As a "power user" I think that the best I can hope for is to write a severely crippled version of the extensions I'd actually like to have; in other words, that it's not worth the trouble. I'd like to write extensions for the things I'd like to have automated in Emacs, for example project support with automated tag-table update on file writing. There are a few projects on this that lack integration, documentation, extensibility and so forth. The best one is probably CEDET, for which I believe the Greenspun's 10th rule can be applied. EDIT: To comment Larry Coleman's answer I'm pretty sure I can pick elisp programming but the extensions I have in mind don't exist yet despite their relative simplicity and the effort more knowledgeable people poured into related projects.This makes me wonder whether it is so because of the way emacs is developed, i.e. people tend to write their own little extensions without coordination, or its implementation, its extension language not being able to keep up with the growing complexity.

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• My 2D collision code does not work as expected. How do I fix it?

  - by farmdve

  I have a simple 2D game with a tile-based map. I am new to game development, I followed the LazyFoo tutorials on SDL. The tiles are in a bmp file, but each tile inside it corresponds to an internal number of the type of tile(color, or wall). The game is simple, but the code is a lot so I can only post snippets. // Player moved out of the map if((player.box.x < 0)) player.box.x += GetVelocity(player, 0); if((player.box.y < 0)) player.box.y += GetVelocity(player, 1); if((player.box.x > (LEVEL_WIDTH - DOT_WIDTH))) player.box.x -= GetVelocity(player, 0); if((player.box.y > (LEVEL_HEIGHT - DOT_HEIGHT))) player.box.y -= GetVelocity(player, 1); // Now that we are here, we check for collisions if(touches_wall(player.box)) { if(player.box.x < player.prev_x) { player.box.x += GetVelocity(player, 0); } if(player.box.x > player.prev_x) { player.box.x -= GetVelocity(player, 0); } if(player.box.y < player.prev_y) { player.box.y += GetVelocity(player, 1); } if(player.box.y > player.prev_y) { player.box.y -= GetVelocity(player, 1); } } player.prev_x = player.box.x; player.prev_y = player.box.y; Let me explain, player is a structure with the following contents typedef struct { Rectangle box; //Player position on a map(tile or whatever). int prev_x, prev_y; // Previous positions int key_press[3]; // Stores which key was pressed/released. Limited to three keys. E.g Left,right and perhaps jump if possible in 2D int velX, velY; // Velocity for X and Y coordinate. //Health int health; bool main_character; uint32_t jump_ticks; } Player; And Rectangle is just a typedef of SDL_Rect. GetVelocity is a function that according to the second argument, returns the velocity for the X or Y axis. This code I have basically works, however inside the if(touches_wall(player.box)) if statement, I have 4 more. These 4 if statements are responsible for detecting collision on all 4 sides(up,down,left,right). However, they also act as a block for any other movement. Example: I move down the object and collide with the wall, as I continue to move down and still collide with the wall, I wish to move left or right, which is indeed possible(not to mention in 3D games), but remember the 4 if statements? They are preventing me from moving anywhere. The original code on the LazyFoo Productions website has no problems, but it was written in C++, so I had to rewrite most of it to work, which is probably where the problem comes from. I also use a different method of moving, than the one in the examples. Of course, that was just an example. I wish to be able to move no matter at which wall I collide. Before this bit of code, I had another one that had more logic in there, but it was flawed.

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• How to avoid the exception “Substitution controls cannot be used in cached User Controls or cached M

  - by DigiMortal

  Recently I wrote example about using user controls with donut caching. Because cache substitutions are not allowed inside partially cached controls you may get the error Substitution controls cannot be used in cached User Controls or cached Master Pages when breaking this rule. In this posting I will introduce some strategies that help to avoid this error. How Substitution control checks its location? Substitution control uses the following check in its OnPreRender method. protected internal override void OnPreRender(EventArgs e) {     base.OnPreRender(e);     for (Control control = this.Parent; control != null;          control = control.Parent)     {         if (control is BasePartialCachingControl)         {             throw new HttpException(SR.GetString("Substitution_CannotBeInCachedControl"));         }     } } It traverses all the control tree up to top from its parent to find at least one control that is partially cached. If such control is found then exception is thrown. Reusing the functionality If you want to do something by yourself if your control may cause exception mentioned before you can use the same code. I modified the previously shown code to be method that can be easily moved to user controls base class if you have some. If you don’t you can use it in controls where you need this check. protected bool IsInsidePartialCachingControl() {     for (Control control = Parent; control != null;         control = control.Parent)         if (control is BasePartialCachingControl)             return true;       return false; } Now it is up to you how to handle the situation where your control with substitutions is child of some partially cache control. You can add here also some debug level output so you can see exactly what controls in control hierarchy are cached and cause problems.

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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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• Ask the Readers: Which Browser is a Must-Have for You on Linux?

  - by Asian Angel

  Linux systems all come with their own particular set of default browsers, but those browsers may not be the ones you want or need. This week we would like to know which browser (or browsers) are considered “must-have” on your Linux systems. As a general rule many Linux distributions have Firefox and/or Konqueror as one of the default installation browsers. During this past year the open source browser Chromium has also been gaining a lot of traction as a default install for systems. For most people these browsers are the ones that they like best or feel work well enough to not make any changes. But there are other people who want more than what is available with a default system install. They may favor a particular browser for its’ extensibility or speed…others prefer a particular browser for its’ features or minimalist UI. Whatever your preferences may be, there is a browser out there to fit your style. Some people may even prefer to run only bleeding edge nightly releases or add them in with their current browsers. The important part is that you have choices when it comes to your Linux system. What we would like to know this week is which browser or browsers you make sure are always installed on your Linux systems. Does the Linux system you use already have your favorite browser installed as part of the default set? Maybe you are content with using the default set of browsers that come with the system. Or perhaps you prefer to rework the entire browser setup on your system by removing the defaults and adding your favorites. Let us know which browsers you consider “must have” and why in the comments! Note: You can make up to two selections on today’s poll since most people will likely have more than one browser that they make certain is always installed. How-To Geek Polls require Javascript. Please Click Here to View the Poll. Latest Features How-To Geek ETC How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC BotSync Enables Secure FTP File Synchronization on Android Devices Enjoy Beautiful City Views with the Cityscape Theme for Windows 7 Luigi Installs Any OS on Google’s Cr-48 Notebook DIY iPad Stylus Offers Pen-Based Interaction on the Cheap Serene Blue Ubuntu Wallpaper for Your Desktop Enjoy Old School Style Video Game Fun with Chicken Invaders

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• Defining a service layer: the text-based adventure

  - by Stacy Vicknair

  Applications these days have more options than ever for a user interface, and it’s only going to grow. A successful product might require native applications for mobile devices, a regular web implementation, or even a gaming console. These systems often will be centralized and data driven. The solution is one that’s fairly solitary, a service layer! Simply put, take what’s shared and put it behind a physical or abstract layer that defines the boundary between the specific user interface and the shared content.   I know, I know, none of this is complicated. But some times it can be difficult to discern what belongs on which side of the line. For instance, say we’re creating a service that will provide content for both an ASP.NET MVC application and a WP7 application. Although the content served to each application is the same, there are different paradigms and patterns for displaying that data in the different environments. In ASP.NET MVC, you may create a model specific to a page that combines necessary information. In the WP7 application you might require different sets of data that you will connect via MVVM with the view. The general rule of thumb is that any shared content, business rules, or data should exist separately. Any element that is specific to the current UI implementation should be included in a separate library or with the UI implementation itself. The WP7 application doesn’t need my MVC specific model classes. My MVC application doesn’t require those INotifyPropertyChanged viewmodels that the WP7 application depends on. In both cases, there should be additional processing done above the service layer to massage the data to the application’s specific needs.   Service-ocalypse: the text based adventure What helps me the most about deciding whether or not something belongs coupled to the UI implementation or in the shared implementation is thinking of the simplest implementation you could have: a console application. You might have played a game like Peasant’s Quest: The console app is the text based adventure game version of your application. If you’re service was consumed in its simplest form, you would simply have a console based API for it that issues requests. Maybe those requests aren’t SWIM TO BOAT, but they might be CREATE USER JOHN. If I issue a request, I expect that request to be issued to the service. If the service has any exceptions or issues with my input, that business logic should be encapsulated in that service, not implemented in the UI. The service layer should be your functional application in its entirety, and anything above that layer should only assist with the display of that information.

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• Why Apple’s New SDK Limitation is So Offensive

  - by TStewartDev

  I am not an Apple fanboy, nor have I ever been. However, I have owned a Mac, an iPod, and an iPhone in my lifetime, and for more than a decade, I have defended Apple against the untruths that the haters so enjoy spewing. I encouraged my wife to buy a MacBook when she needed a new laptop two years ago, and I often recommend them to my friends and relatives. I have proudly and happily used my first generation iPhone for nearly three years. Now, for the first time in well over ten years, I find myself ready to swear off Apple and encourage everyone I know to do the same. I was disappointed when Apple wouldn't allow native apps, but I still bought the iPhone. I've stomached their ambiguous app approval process even though it's apparent that Steve may just reject your app because he doesn't like you or feels threatened by you (I'm still lamenting the rejection of the Google Voice app). But, as a developer, I can no longer tolerate Apple's terms and the kind of totalitarian control they indicate Apple wants. In case you are not already familiar, Apple has dictated in their OS 4.0 SDK license agreement (the now infamous Section 3.3.1) that all apps developed for the iPhone must be coded in C, C++, or Objective C, and moreover, that using any cross-compiling platforms is a violation of the agreement. For those of you who aren't developers, let me try to illustrate why this angers those of us who are. Imagine you're a professional writer. You've had articles published in some journals and magazines, and you've got a couple popular books out there, too. You've got an idea for a new book, and so you take it to your publisher. Your publisher agrees that it's a good idea. "But," says the publisher, "we want to hold our books to a tighter standard so that our readers get the experience we want them to have. Therefore, from now on, all our writers may only use words from this list of the 10,000 most common English words. Furthermore, if you cite any other works or quote anyone, they must comply with that same list, or you'll have to rewrite the entire work as well in case our readers want to look up your citation." What do you do? If your work is a children's book, this probably isn't a big deal to you. If it's an autobiography, textbook, or even a novel, though, you're going to have a lot of trouble describing your content with only common words. It's going to take you longer to complete your book, too, since you'll be looking up less common words frequently to see if you can use them. You could always go to another publisher, but this one has the best ability to distribute your book. The next largest distributor can only do a quarter as much. You could abandon the project altogether, but then everyone loses. Isn't this a silly scenario? Who would put such a limitation on writers? Yet this is very much what Apple is doing. They are using their dominant position in the market to coerce developers to write their apps exclusively for the iPhone OS by making it too expensive to write for multiple platforms. It is at least a threefold attack, striking at Adobe who is set to release a compiler that lets Flash source be compiled to iPhone binaries; striking at Google whose Android platform stands the best chance at the moment of providing serious competition to the iPhone; and reinforcing their own strong position by keeping popular apps exclusively to iPhone. And while developers are already very upset about this, the sad fact is that most of us will cave and give in to Apple because consumers don't know any better. They will continue to buy Apple's toy forcing developers to play Apple's maniacal game in order to make any money, at least until Steve Jobs decides he doesn't like them or he intends to release a competing application (bye-bye OpenFeint). Apple has been kept in check on the desktop front by a very dominant Microsoft, but I'm afraid that their success with iPods, iTunes, and iPhones has created a monster that we may have to bear until it is slain by an anti-trust suit or dies with the retirement of Steve Jobs.

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• My 2011 Professional Development Goals

  - by kerry

  I thought it might be a good idea to post some professional goals for 2011.  Hopefully, I can look at this list at the end of the year and have accomplished most of them. Release an Android app to the marketplace – I figured I would put this first because I have one that I have been working on for a while and it is about ready.  Along with this, I would like to start another one and continue to develop my Android skills. Contribute free software to the community – Again, I have an SMF plugin that will fill this requirement nicely.  Just need to give it some polish and release it.  That’s not all, I would like to add a few more libraries on github, or possibly contribute to an open source project. Regularly attend a user group meetings outside of Java – A great way to meet people and learn new things. Obtain the Oracle Certified Web Developer Certification – I got the SCJP a few years ago and would like to obtain another one.  One step closer to Certified Enterprise Architect. Learn scala – As a language geek, I like to stick to the Pragmatic Programmer’s ‘learn a new language every year’ rule (last year was Ruby).  Scala presents some new concepts all wrapped in a JVM-based OOP language.  Time to dig in. Write an app using JSF – New JEE 6 features are pretty slick.  I want to really leverage them in an app. Present at a user group meeting – Last but not least, I would like to improve my public speaking and skills in presenting.  Also, is a great reason to dig in to some latest and greatest tech. Use git more, and more effectively – Trying to move all my personal projects from Subversion to Git. That’s it.  A little daunting, but I am confident I can at least touch on most of these and it’s a great roadmap to my professional development.

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• Perfect is the enemy of “Good Enough”

  - by Daniel Moth

  This is one of the quotes that I was against, but now it is totally part of my core beliefs: "Perfect is the enemy of Good Enough" Folks used to share this quote a lot with me in my early career and my frequent interpretation was that they were incompetent people that were satisfied with mediocrity, i.e. I ignored them and their advice. (Yes, I went through an arrogance phase). I later "grew up" and "realized" that they were missing the point, so instead of ignoring them I would retort: "Of course we have to aim for perfection, because as human beings we'll never achieve perfection, so by aiming for perfection we will indeed achieve good enough results". (Yes, I went through a smart ass phase). Later I grew up a bit more and "understood" that what I was really being told is to finish my work earlier and move on to other things because by trying to perfect that one thing, another N things that I was responsible for were suffering by not getting my attention - all things on my plate need to move beyond the line, not just one of them to go way over the line. It is really a statement of increasing scale and scope. To put it in other words, getting PASS grades on 10 things is better than getting an A+ with distinction on 1-2 and a FAIL on the rest. Instead of saying “I am able to do very well these X items” it is best if you can say I can do well enough on these X * Y items”, where Y > 1. That is how breadth impact is achieved. In the future, I may grow up again and have a different interpretation, but for now - even though I secretly try to "perfect" things, I try not to do that at the expense of other responsibilities. This means that I haven't had anybody quote that saying to me in a while (or perhaps my quality of work has dropped so much that it doesn't apply to me any more - who knows :-)). Wikipedia attributes the quote to Voltaire and it also makes connections to the “Law of diminishing returns”, and to the “80-20 rule” or “Pareto principle”… it commonly takes 20% of the full time to complete 80% of a task while to complete the last 20% of a task takes 80% of the effort …check out the Wikipedia entry on “Perfect is the enemy of Good” and its links. Also use your favorite search engine to search and see what others are saying (Bing, Google) – it is worth internalizing this in a way that makes sense to you… Comments about this post by Daniel Moth welcome at the original blog.

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• Is this Hybrid of Interface / Composition kosher?

  - by paul

  I'm working on a project in which I'm considering using a hybrid of interfaces and composition as a single thing. What I mean by this is having a contain*ee* class be used as a front for functionality implemented in a contain*er* class, where the container exposes the containee as a public property. Example (pseudocode): class Visibility(lambda doShow, lambda doHide, lambda isVisible) public method Show() {...} public method Hide() {...} public property IsVisible public event Shown public event Hidden class SomeClassWithVisibility private member visibility = new Visibility(doShow, doHide, isVisible) public property Visibility with get() = visibility private method doShow() {...} private method doHide() {...} private method isVisible() {...} There are three reasons I'm considering this: The language in which I'm working (F#) has some annoyances w.r.t. implementing interfaces the way I need to (unless I'm missing something) and this will help avoid a lot of boilerplate code. The containee classes could really be considered properties of the container class(es); i.e. there seems to be a fairly strong has-a relationship. The containee classes will likely implement code which would have been pretty much the same when implemented in all the container classes, so why not do it once in one place? In the above example, this would include managing and emitting the Shown/Hidden events. Does anyone see any isseus with this Composiface/Intersition method, or know of a better way? EDIT 2012.07.26 - It seems a little background information is warranted: Where I work, we have a bunch of application front-ends that have limited access to system resources -- they need access to these resources to fully function. To remedy this we have a back-end application that can access the needed resources, with which the front-ends can communicate. (There is an API written for the front-ends for accessing back-end functionality as though it were part of the front-end.) The back-end program is out of date and its functionality is incomplete. It has made the transition from company to company a couple of times and we can't even compile it anymore. So I'm trying to rewrite it in my spare time. I'm trying to update things to make a nice(r) interface/API for the front-ends (while allowing for backwards compatibility with older front-ends), hopefully something full of OOPy goodness. The thing is, I don't want to write the front-end API after I've written pretty much the same code in F# for implementing the back-end; so, what I'm planning on doing is applying attributes to classes/methods/properties that I would like to have code for in the API then generate this code from the F# assembly using reflection. The method outlined in this question is a possible alternative I'm considering instead of implementing straight interfaces on the classes in F# because they're kind of a bear: In order to access something of an interface that has been implemented in a class, you have to explicitly cast an instance of that class to the interface type. This would make things painful when getting calls from the front-ends. If you don't want to have to do this, you have to call out all of the interface's methods/properties again in the class, outside of the interface implementation (which is separate from regular class members), and call the implementation's members. This is basically repeating the same code, which is what I'm trying to avoid!

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• Options for different domain and hosting

  - by Carl

  The situation I have a hosting service (one.com) on which I have installed a wordpress.org site in a subdirectory 'wordpress': myhost.com/wordpress/ (myhost.com is actually my own domain, but it already has contents and I don't want wordpress/ to appear in the root of that domain.) I want to use a second domain for this site. Thinking I would be able to forward to the wordpress site without problems, I registered the domain at GoDaddy.com: mydomain.com What I want So when my visitors type in mydomaind.com, I want them to see the contents on myhost.com/wordpress/, and the same for all subpages (mydomain.com/a/subpage fetches from myhost.com/wordpress/a/subpage). Just a redirect isn't enough, I want my visitors to see only mydomain.com as their domain. Some notes If I set up forward with URL masking at GoDaddy, they just give a full frame, pointing to myhost.com/wordpress/. This isn't good enough for me, since mydomain.com will always show up in the adress bar, also for subpages (I want mydomain/a/subpage to show in the adress bar for a subpage). I believe this could in principle be done with a .htaccess file with URL rewriting, but I have no hosting with GoDaddy so I can't upload such a file there. Hosting with GoDaddy is very expensive (of course) so I don't want to do that. I don't think I can use DNS settings; the host of mydomain.com says they don't allow anyone else to point to their name servers. If possible, I wouldn't want to re-install the wordpress site, it would take quite some time. I'd prefer to keep it at myhost.com/wordpress/ (if possible) Anything involving transferring the domain is supposed to take 5-7 working days. I would need my site up-and-running earlier than that, so I'd like to avoid it if possible. Am I locked in? As it seems, I am rather locked-in with GoDaddy. I can't use the domain with .htaccess since I can't upload such a file (and won't pay for hosting by GoDaddy). I can't use any of their forward options since none of them do what I want (one just forwards, the one that masks the URL does it with frames). Would you agree? Possible solutions Transfer the domain to any hosting service with reasonable hosting pricing, as opposed to GoDaddy (I'd probably use one.com, the same host as for myhost.com, in that case), and there either re-install wordpress on the new account, or use .htaccess with URL rewrite on the new account to fetch the contents from myhost.com/wordpress/. Can this be set-up to work with sub-pages as well? And visitors won't ever see "myhost.com/wordpress", just "mydomain.com"? E.i., mydomain.com/a/subpage/ wold fetch from myhost.com/wordpress/a/subpage/? This might be a long shot but: Find some free (preferrably) hosting allowing to point to their nameservers Make DNS settings at GoDaddy so that my domain appears at the site above at that site, put a .htaccess file with URL rewriting to forward to myhost.com/wordpress/ Could this be possible? What services could I use in that case? As I see it, this would be the only way not to have to transfer a domain (taking 5-7 working days) and not having to re-install the wordpress site. Sorry for the long question. All info and ideas are welcome.

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• Is IE9 a modern browser?

  - by anirudha

  Is IE9 a modern browser? i show you a post who compare IE as well as they compare chrome. Is IE9 a modern browser? well Are you thing that they make something bettter then thing another that what Firefox and chrome do whenever Microsoft do this. that's point that Microsoft always blast IE because they make version upon version not upon update like Firefox make 3.6.14 after 3.6.13 and chrome give update soon as possible but IE not come soon. they will thing for making 10 instead of giving update on 9. well what they tell us new. they make fool public everytime i believe they make fool public as same as today they maked for version 9 they show developer tool in 9 have three new tabs or pael are this enough. whenever  in chrome and firefox their is many plugin who make development easier IE still have a developer tool who not have enough power like Firebug in Firefox. they show performance but forget luna user [window xp] and their IE never runs on other plateform but chrome and firefox can. no customization in IE whenever chrome and firefox have uncountable plugin and addons. show features now in IE who already implemented in firefox very early. well their is no rule that static goes right every time not sure that IE and Firefox both are right in their language. their is no one predict what thing goes better in future. so well keep a thing in mind never wasted time and also thing to make task easier even you need to use sollution opensource or closesoure inside or outside MS does not matter. well everyone tell you much more then they do even IE and some other. they never tell you this thing not in IE but in another can be found they never tell you use other whenever you need a thing and never can be found in their software. you need to more beware of IE because they make them commorcial not really for public if really then why they stop wxp user to use them as well firefox and chrome never force. because they need a thing that force more then more copy of windows sale. so they thing to add a thing in window 8. the IE9 they thing to make before that they thing to make  this for windows 8. they always force user to purchase this for this. this for this. and this trick sell their software. well outside MS Mozilla and Chrome all behave better with user and their feedback. they respect user their privacy and feedback. if you not believe that how much problem you found in IE and they got solved soon as in chrome and firefox bug kill soon. because IE not opensource we need to  boycutt them secondly their is no customization then they make user task easier even with twitter and facebook.

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• Java @Contented annotation to help reduce false sharing

  - by Dave

  See this posting by Aleksey Shipilev for details -- @Contended is something we've wanted for a long time. The JVM provides automatic layout and placement of fields. Usually it'll (a) sort fields by descending size to improve footprint, and (b) pack reference fields so the garbage collector can process a contiguous run of reference fields when tracing. @Contended gives the program a way to provide more explicit guidance with respect to concurrency and false sharing. Using this facility we can sequester hot frequently written shared fields away from other mostly read-only or cold fields. The simple rule is that read-sharing is cheap, and write-sharing is very expensive. We can also pack fields together that tend to be written together by the same thread at about the same time. More generally, we're trying to influence relative field placement to minimize coherency misses. Fields that are accessed closely together in time should be placed proximally in space to promote cache locality. That is, temporal locality should condition spatial locality. Fields accessed together in time should be nearby in space. That having been said, we have to be careful to avoid false sharing and excessive invalidation from coherence traffic. As such, we try to cluster or otherwise sequester fields that tend to written at approximately the same time by the same thread onto the same cache line. Note that there's a tension at play: if we try too hard to minimize single-threaded capacity misses then we can end up with excessive coherency misses running in a parallel environment. Theres no single optimal layout for both single-thread and multithreaded environments. And the ideal layout problem itself is NP-hard. Ideally, a JVM would employ hardware monitoring facilities to detect sharing behavior and change the layout on the fly. That's a bit difficult as we don't yet have the right plumbing to provide efficient and expedient information to the JVM. Hint: we need to disintermediate the OS and hypervisor. Another challenge is that raw field offsets are used in the unsafe facility, so we'd need to address that issue, possibly with an extra level of indirection. Finally, I'd like to be able to pack final fields together as well, as those are known to be read-only.

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• Strategy for avoiding duplicate object ids for data shared across devices using iCloud

  - by rmaddy

  I have a data intensive iOS app that is not using CoreData nor does it support iCloud synching (yet). All of my objects are created with unique keys. I use a simple long long initialized with the current time. Then as I need a new key I increment the value by 1. This has all worked well for a few years with the app running isolated on a single device. Now I want to add support for automatic data sync across devices using iCloud. As my app is written, there is the possibility that two objects created on two different devices could end up with the same key. I need to avoid this possibility. I'm looking for ideas for solving this issue. I have a few requirements that the solution must meet: 1) The key needs to remain a single integral data type. Converting all existing keys to a compound key or to a string or other type would affect the entire code base and likely result in more bugs than it's worth. 2) The solution can't depend on an Internet connection. A user must be able to run the app and add data even with no Internet connection. The data should still resolve properly later when the data syncs through iCloud once a connection is available. I'll accept one exception to this rule. If no other option is available, I may be open to requiring an Internet connection the first time the app's data is initialized. One idea I have been toying around with in my head is logically splitting the integer key into two parts. The high 4 or 5 bits could be used as some sort of device id while the rest represents the actual key. The fuzzy part is figuring out how to come up with non-conflicting device ids that fit in a few bits. This should be viable since I don't need to deal will millions of devices. I just need to deal with the few devices that would be shared by a given iCloud account. I'm open to suggestions. Thanks.

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• Is Visual Source Safe (The latest Version) really that bad? Why? What's the Best Alternative? Why? [closed]

  - by hanzolo

  Over the years I've constantly heard horror stories, had people say "Real Programmers Dont Use VSS", and so on. BUT, then in the workplace I've worked at two companies, one, a very well known public facing high traffic website, and another high end Financial Services "Web-Based" hosted solution catering to some very large, very well known companies, which is where I currently Reside and everything's working just fine (KNOCK KNOCK!!). I'm constantly interfacing with EXTREMELY Old technology with some of these financial institutions.. OLD LIKE YOU WOULDN'T BELIEVE.. which leads me to the conclusion that if it works "LEAVE IT", and that maybe there's some value in old technology? at least enough value to overrule a rewrite!? right?? Is there something fundamentally flawed with the underlying technology that VSS uses? I have a feeling that if i said "someone said VSS Sucks" they would beg to differ, most likely give me this look like i dont know -ish, and I'd never gain back their respect and my credibility (well, that'll be hard to blow.. lol), BUT, give me an argument that I can take to someone whose been coding for 30 years, that builds Platforms that leverage current technology (.NET 3.5 / SQL 2008 R2 ), write's their own ORM with scaffolding and is able to provide a quality platform that supports thousands of concurrent users on a multi-tenant hosted solution, and does not agree with any benefits from having Source Control Integrated, and yet uses the Infamous Visual Source Safe. I have extensive experience with TFS up to 2010, and honestly I think it's great when a team (beyond developers) can embrace it. I've worked side by side with someone whose a die hard SVN'r and from a purist standpoint, I see the beauty in it (I need a bit more, out of my SS, but it surely suffices). So, why are such smarties not running away from Visual Source Safe? surely if it was so bad, it would've have been realized by now, and I would not be sitting here with this simple old, Check In, Check Out, Version Resistant, Label Intensive system. But here I am... I would love to drop an argument that would be the end all argument, but if it's a matter of opinion and personal experience, there seems to be too much leeway for keeping VSS. UPDATE: I guess the best case is to have the VSS supporters check other people's experiences and draw from that until we (please no) experience the breaking factor ourselves. Until then, i wont be engaging in a discussion to migrate off of VSS.. UPDATE 11-2012: So i was able to convince everyone at my work place that since MS is sun downing Visual Source Safe it might be time to migrate over to TFS. I was able to convince them and have recently upgraded our team to Visual Studio 2012 and TFS 2012. The migration was fairly painless, had to run analyze.exe which found a bunch of errors (not sure they'll ever affect the project) and then manually run the VSSConverter.exe. Again, painless, except it took 16 hours to migrate 5 years worth of everything.. and now we're on TFS.. much more integrated.. much more cooler.. so all in all, VSS served it's purpose for years without hick-up. There were no horror stories and Visual Source Save as source control worked just fine. so to all the nay sayers (me included). there's nothing wrong with using VSS. i wouldnt start a new project with it, and i would definitely consider migrating to TFS. (it's really not super difficult and a new "wizard" type converter is due out any day now so migrating should be painless). But from my experience, it worked just fine and got the job done.

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