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• Package management system corrupted. Cannot install or remove packages. U12.04LTS

  - by user271490

  Having read other posts, I believe that this may be less about samba than about update system. Below is the log file of the failed installation of Samba. I have been trying without success to install/outstall samba so that I could install anything else ... I cannot either install or remove samba using either update-manager or apt-get (nor indeed Software Centre). One of the errors that I have had to correct is the presence after "removal" (failed) of /usr/share/system-config-samba directory which finally allowed itself to be deleted. That, however was then ... I have U12.04LTS. running on release 63 because I allowed the upgrade to 64 this morning which fell over - no output to monitor - obviously even less support for my graphic chip than I am suffering already (see other posts in this forum). According to my interpretation of the dpkg returned errors there may be some problem with the package files, but if this is the case then it is on servers 'main', 'nantes uni fr' and 'best fr' at the very least if not everywhere. The suggestions offered at Package operation failed and elsewhere have not worked for me. This linked post suggests that a similar error is present in other packages, or that the error is in the 'update system' I have tried ... sudo apt-get remove samba ... autoremove ... install samba ... clean ... update -f all of the above In update-manager I have tried the "reload packages list" which fails to terminate because of the error. I have tried to install and remove samba from the software centre ... :( I am at a loss ... I need help, please! Firstly to recover my apt-get/update-manager/Software Centre so that I can at least carry on with my continuing installation - up to communicating with home network hence need for samba - which brings me to my second requirement ... samba. PS is the issue about "MaxReports" associated or apart? UPDATE! Being heartily sick of restarting FF every 5 seconds I thought I'd try again with Chromium ... and got the same errors from dpkg about corrupt compressed package - coincidence? Of course this was no longer in clipboard when I got here because apport has just errored ... AAARRRGGGH!!! Why does every error clear the clipboard? Thanks for any and all help!! installArchives() failed: Preconfiguring packages ... ... snip (Reading database ... ... snip (Reading database ... 184858 files and directories currently installed.) Unpacking samba (from .../samba_2%3a3.6.3-2ubuntu2.10_i386.deb) ... dpkg-deb (subprocess): data: internal gzip read error: ': data error' dpkg-deb: error: subprocess returned error exit status 2 dpkg: error processing /var/cache/apt/archives/samba_2%3a3.6.3-2ubuntu2.10_i386.deb (--unpack): subprocess dpkg-deb --fsys-tarfile returned error exit status 2 No apport report written because MaxReports is reached already Selecting previously unselected package system-config-samba. Unpacking system-config-samba (from .../system-config-samba_1.2.63-0ubuntu5_all.deb) ... Processing triggers for ureadahead ... ureadahead will be reprofiled on next reboot Processing triggers for ufw ... Processing triggers for man-db ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Processing triggers for hicolor-icon-theme ... Errors were encountered while processing: /var/cache/apt/archives/samba_2%3a3.6.3-2ubuntu2.10_i386.deb Error in function: dpkg: dependency problems prevent configuration of system-config-samba: system-config-samba depends on samba; however: Package samba is not installed. dpkg: error processing system-config-samba (--configure): dependency problems - leaving unconfigured

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• How should I plan the inheritance structure for my game?

  - by Eric Thoma

  I am trying to write a platform shooter in C++ with a really good class structure for robustness. The game itself is secondary; it is the learning process of writing it that is primary. I am implementing an inheritance tree for all of the objects in my game, but I find myself unsure on some decisions. One specific issue that it bugging me is this: I have an Actor that is simply defined as anything in the game world. Under Actor is Character. Both of these classes are abstract. Under Character is the Philosopher, who is the main character that the user commands. Also under Character is NPC, which uses an AI module with stock routines for friendly, enemy and (maybe) neutral alignments. So under NPC I want to have three subclasses: FriendlyNPC, EnemyNPC and NeutralNPC. These classes are not abstract, and will often be subclassed in order to make different types of NPC's, like Engineer, Scientist and the most evil Programmer. Still, if I want to implement a generic NPC named Kevin, it would nice to be able to put him in without making a new class for him. I could just instantiate a FriendlyNPC and pass some values for the AI machine and for the dialogue; that would be ideal. But what if Kevin is the one benevolent Programmer in the whole world? Now we must make a class for him (but what should it be called?). Now we have a character that should inherit from Programmer (as Kevin has all the same abilities but just uses the friendly AI functions) but also should inherit from FriendlyNPC. Programmer and FriendlyNPC branched away from each other on the inheritance tree, so inheriting from both of them would have conflicts, because some of the same functions have been implemented in different ways on the two of them. 1) Is there a better way to order these classes to avoid these conflicts? Having three subclasses; Friendly, Enemy and Neutral; from each type of NPC; Engineer, Scientist, and Programmer; would amount to a huge number of classes. I would share specific implementation details, but I am writing the game slowly, piece by piece, and so I haven't implemented past Character yet. 2) Is there a place where I can learn these programming paradigms? I am already trying to take advantage of some good design patterns, like MVC architecture and Mediator objects. The whole point of this project is to write something in good style. It is difficult to tell what should become a subclass and what should become a state (i.e. Friendly boolean v. Friendly class). Having many states slows down code with if statements and makes classes long and unwieldy. On the other hand, having a class for everything isn't practical. 3) Are there good rules of thumb or resources to learn more about this? 4) Finally, where does templating come in to this? How should I coordinate templates into my class structure? I have never actually taken advantage of templating honestly, but I hear that it increases modularity, which means good code.

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• Caching factory design

  - by max

  I have a factory class XFactory that creates objects of class X. Instances of X are very large, so the main purpose of the factory is to cache them, as transparently to the client code as possible. Objects of class X are immutable, so the following code seems reasonable: # module xfactory.py import x class XFactory: _registry = {} def get_x(self, arg1, arg2, use_cache = True): if use_cache: hash_id = hash((arg1, arg2)) if hash_id in _registry: return _registry[hash_id] obj = x.X(arg1, arg2) _registry[hash_id] = obj return obj # module x.py class X: # ... Is it a good pattern? (I know it's not the actual Factory Pattern.) Is there anything I should change? Now, I find that sometimes I want to cache X objects to disk. I'll use pickle for that purpose, and store as values in the _registry the filenames of the pickled objects instead of references to the objects. Of course, _registry itself would have to be stored persistently (perhaps in a pickle file of its own, in a text file, in a database, or simply by giving pickle files the filenames that contain hash_id). Except now the validity of the cached object depends not only on the parameters passed to get_x(), but also on the version of the code that created these objects. Strictly speaking, even a memory-cached object could become invalid if someone modifies x.py or any of its dependencies, and reloads it while the program is running. So far I ignored this danger since it seems unlikely for my application. But I certainly cannot ignore it when my objects are cached to persistent storage. What can I do? I suppose I could make the hash_id more robust by calculating hash of a tuple that contains arguments arg1 and arg2, as well as the filename and last modified date for x.py and every module and data file that it (recursively) depends on. To help delete cache files that won't ever be useful again, I'd add to the _registry the unhashed representation of the modified dates for each record. But even this solution isn't 100% safe since theoretically someone might load a module dynamically, and I wouldn't know about it from statically analyzing the source code. If I go all out and assume every file in the project is a dependency, the mechanism will still break if some module grabs data from an external website, etc.). In addition, the frequency of changes in x.py and its dependencies is quite high, leading to heavy cache invalidation. Thus, I figured I might as well give up some safety, and only invalidate the cache only when there is an obvious mismatch. This means that class X would have a class-level cache validation identifier that should be changed whenever the developer believes a change happened that should invalidate the cache. (With multiple developers, a separate invalidation identifier is required for each.) This identifier is hashed along with arg1 and arg2 and becomes part of the hash keys stored in _registry. Since developers may forget to update the validation identifier or not realize that they invalidated existing cache, it would seem better to add another validation mechanism: class X can have a method that returns all the known "traits" of X. For instance, if X is a table, I might add the names of all the columns. The hash calculation will include the traits as well. I can write this code, but I am afraid that I'm missing something important; and I'm also wondering if perhaps there's a framework or package that can do all of this stuff already. Ideally, I'd like to combine in-memory and disk-based caching.

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• Learn Many Languages

  - by Jeff Foster

  My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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• Top 5 Reasons to Invest in Enterprise 2.0 Technologies

  - by kellsey.ruppel(at)oracle.com

  In 2010, Oracle's portal, content management, and collaboration solutions evolved rapidly, supported by increasingly deep integrations across Oracle Fusion Middleware and the entire Oracle stack. In light of these developments, we asked Vince Casarez, vice president of Enterprise 2.0 product management, for his top five reasons to invest in Enterprise 2.0 (E2.0) technologies--including real-world examples of businesses already realizing the benefits of next-generation E2.0 technologies. 1. Provide a modern user experience As E2.0 technologies gain widespread adoption, customers and employees expect intuitive Web experiences that are both interactive and community-based. By partnering with Oracle, Alcatel-Lucent Enterprise Group is already making that happen. With 76,000 employees and operations in more than 100 countries, the company wanted a streamlined, personalized user experience with more relevant content in fewer clicks. Working with Oracle, they created a global support portal that supports personalization and integration with Oracle Business Intelligence Enterprise Edition and Oracle E-Business Suite--and drives collaboration with tools such as wikis, blogs, and forums. Learn more about Alcatel-Lucent Enterprise Group's Global Support Portal in this Webcast. 2. Improve productivity and collaboration As E2.0 technologies mature, Oracle anticipates companies moving beyond the idea of simply creating yet another Facebook-like destination for its employees, and instead shaping work environments around specific business tasks. After rapid growth--both organic and through acquisition--construction and infrastructure services leader Balfour Beatty found itself with multiple homegrown intranet sites with very minimal content-sharing capabilities. Today, thanks to Oracle WebCenter Suite, Oracle WebCenter Spaces, Oracle WebCenter Services, and Oracle Universal Content Management, Balfour Beatty is benefiting from collaborative workspaces, a central place to use and work with documents, and unified search across content. 3. Leverage business processes and applications Modern portals are now able to integrate users, content, and business processes in unprecedented ways. To take advantage of these new possibilities, leading dairy provider Land O'Lakes has implemented a fully integrated ERP solution together with Oracle's ECM platform. As a result, Land O'Lakes has been able to achieve better information management and compliance, increased adoption rates for enterprise tools, and increased business process efficiency thanks to more effective information sharing and collaboration. 4. Enhance customer and supplier relationships Companies have begun to move beyond the idea that E2.0 simply means enabling customer reviews or embedding chat functionality. They are taking E2.0 to the next level and providing interactive experiences for their customers. For example, to enhance customer and supplier relationships, Wind River, a global leader in device software optimization, successfully partnered with Oracle to: Integrate ERP and ECM content to provide customers the latest and most relevant support information for products they own Enable customers to personalize their support experience and receive updates regarding patches, application notes, and other relevant content Enable discussions, wikis, and blogs for more efficient collaboration 5. Increase business visibility and responsiveness By strategically embedding collaboration and communication tools into specific business contexts, companies significantly increase visibility into changing business conditions--and can respond much more agilely. Texas A&M University System--one of the largest systems of higher education in the U.S.--partnered with Oracle to create a unified repository that would enable the retrieval of research and grant data from disparate systems via an Enterprise 2.0 user interface. By enabling researchers to customize their own portals with easy-to-use tools, they have also been able to significantly reduce their reliance on the IT department. Learn how other Oracle customers are leveraging Enterprise 2.0 technologies.

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• Running Powershell from within SharePoint

  - by Norgean

  Just because something is a daft idea, doesn't mean it can't be done. We sometimes need to do some housekeeping - like delete old files or list items or… yes, well, whatever you use Powershell for in a SharePoint world. Or it could be that your solution has "issues" for which you have Powershell solutions, but not the budget to transform into proper bug fixes. So you create a "how to" for the ITPro guys. Idea: What if we keep the scripts in a list, and have SharePoint execute the scripts on demand? An announcements list (because of the multiline body field). Warning! Let us be clear. This list needs to be locked down; if somebody creates a malicious script and you run it, I cannot help you. First; we need to figure out how to start Powershell scripts from C#. Hit teh interwebs and the Googlie, and you may find jpmik's post: http://www.codeproject.com/Articles/18229/How-to-run-PowerShell-scripts-from-C. (Or MS' official answer at http://msdn.microsoft.com/en-us/library/ee706563(v=vs.85).aspx) public string RunPowershell(string powershellText, SPWeb web, string param1, string param2) { // Powershell ~= RunspaceFactory - i.e. Create a powershell context var runspace = RunspaceFactory.CreateRunspace(); var resultString = new StringBuilder(); try { // load the SharePoint snapin - Note: you cannot do this in the script itself (i.e. add-pssnapin etc does not work) PSSnapInException snapInError; runspace.RunspaceConfiguration.AddPSSnapIn("Microsoft.SharePoint.PowerShell", out snapInError); runspace.Open(); // set a web variable. runspace.SessionStateProxy.SetVariable("webContext", web); // and some user defined parameters runspace.SessionStateProxy.SetVariable("param1", param1); runspace.SessionStateProxy.SetVariable("param2", param2); var pipeline = runspace.CreatePipeline(); pipeline.Commands.AddScript(powershellText); // add a "return" variable pipeline.Commands.Add("Out-String"); // execute! var results = pipeline.Invoke(); // convert the script result into a single string foreach (PSObject obj in results) { resultString.AppendLine(obj.ToString()); } } finally { // close the runspace runspace.Close(); } // consider logging the result. Or something. return resultString.ToString(); } Ok. We've written some code. Let us test it. var runner = new PowershellRunner(); runner.RunPowershellScript(@" $web = Get-SPWeb 'http://server/web' # or $webContext $web.Title = $param1 $web.Update() $web.Dispose() ", null, "New title", "not used"); Next step: Connect the code to the list, or more specifically, have the code execute on one (or several) list items. As there are more options than readers, I'll leave this as an exercise for the reader. Some alternatives: Create a ribbon button that calls RunPowershell with the body of the selected itemsAdd a layout pageSpecify list item from query string (possibly coupled with content editor webpart with html that links directly to this page with querystring)WebpartListing with an "execute" columnList with multiselect and an execute button Etc!Now that you have the code for executing powershell scripts, you can easily expand this into a timer job, which executes scripts at regular intervals. But if the previous solution was dangerous, this is even worse - the scripts will usually be run with one of the admin accounts, and can do pretty much anything...One more thing... Note that as this is running "consoleless" calls to Write-Host will fail. Two solutions; remove all output, or check if the script is run in a console-window or not.  if ($host.Name -eq "ConsoleHost") { Write-Host 'If I agreed with you we'd both be wrong' }

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• Refactoring existing PHP Project. I need some advices

  - by b0x

  i have a small SAS ERP that was written some years ago using PHP. At that time, it didn't used any framework, but the code isn't a mess as i will explain more detailed in the following lines. Nowadays, the project grow and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such Laravel. Although I'd love trying Laravel, I’m a small business and i don't have time/money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers I must separate the "view", because: I want to release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) Release different versions to fit mobile/tablet. Make different types of this product, seeling packages as if it were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing rotines, to quality assurance. My actual structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysqli on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s fies outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But i want to write a manual of our rules. Something that i can give to any new programmer at my companie and he can go on. This is not totally a mess, but It could be better seeing the new practices. What could I do to separate this as MVC, to have multiple VIEW’s. Could you gimme some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc. It would be nice. Thanks!

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• Advice on refactoring PHP Project

  - by b0x

  I have a small SAS ERP that was written some years ago using PHP. At that time, it didn't use any framework, but the code isn't a mess. Nowadays, the project grows and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such as Laravel. Although I'd love trying Laravel, I’m a small business and I don't have time nor money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers Separate the "view", in order to: release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) release different versions to fit mobile/tablet. Make different types of this product, selling packages as if they were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing routines for quality assurance. My current structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysql on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s files outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But I want to write a manual of our rules. Something that I can give to any new programmer at my company and he can go on. This is not totally a mess, but it could be better seeing the new practices. What could I do to separate this as MVC, to have multiple views. Could you give me some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc, would be nice.

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• Would this be a good web application architecture?

  - by Gustav Bertram

  My problem Our MVC based framework does not allow us to cache only part of our output. Ideally we want to cahce static and semi-static bits, and run dynamic bits. In addition, we need to consider data caching that reacts to database changes. My idea The concept I came up with was to represent a page as a tree of XML fragment objects. (I say XML, but I mean XHTML). Some of the fragments are dynamic, and can pull their data directly from models or other sources, but most of the fragments are static scaffolding. If a subtree of fragments is completely static, then I imagine that they could unfold into pure XML that would then be cached as the text representation of their parent element. This process would ideally continue until we are left with a root element that contains all of the static XML, and has a couple of dynamic XML fragments that are resolved and attached to the relevant nodes of the XML tree just before the page is displayed. In addition to separating content into dynamic and static fragments, some fragments could be dynamic and cached. A simple expiry time which propagates up through the XML fragment tree would indicate that a specific fragment should periodically be refreshed. A newspaper section or front page does not need to be updated each second. Minutes or sometimes even longer is sufficient. Other fragments would be dynamic and uncached. Typically too many articles are viewed for them to be cached - the cache would overflow. Some individual articles may be cached if they are extremely popular. Functional notes The folding mechanism could be to be smart enough to judge when it would be more profitable to fold a dynamic cached fragment and propagate the expiry date to the parent fragment, or to keep it separate and simple attach to the XML tree when resolving the page. If some dynamic cached fragments are associated to database objects through mechanisms like a globally unique content id, then changes to the database could trigger changes to the output cache. If fragments store the identifiers of parent fragments, then they could trigger a refolding process that would then include the updated data. A set of pure XML with an ordered array of fragment objects (that each store the identifying information of the node to which they should be attached), can be resolved in a fairly simple way by walking the XML tree, and merging the data from the fragments. Because it is not necessary to parse and construct the entire tree in memory before attaching nodes, processing should be fairly fast. The identifiers of each fragment would be a combination of relevant identity data and the type of fragment object. Cached parent fragments would contain references to these identifiers, in order to then either pull them from the fragment cache, or to run their code. The controller's responsibility is reduced to making changes to the database, and telling the root XML fragment object to render itself. The Question My question has two parts: Is this a good design? Are there any obvious flaws I'm missing? Has somebody else thought of this before? References? Is there an existing alternative that I should consider? A cool templating engine maybe?

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• JavaOne 2012: Nashorn Edition

  - by $utils.escapeXML($entry.author)

  As with my JavaOne 2012: OpenJDK Edition post a while back (now updated to reflect the schedule of the talks), I find it convenient to have my JavaOne schedule ordered by subjects of interest. Beside OpenJDK in all its flavors, another subject I find very exciting is Nashorn. I blogged about the various material on Nashorn in the past, and we interviewed Jim Laskey, the Project Lead on Project Nashorn in the Java Spotlight podcast. So without further ado, here are the JavaOne 2012 talks and BOFs with Nashorn in their title, or abstract:CON5390 - Nashorn: Optimizing JavaScript and Dynamic Language Execution on the JVM - Monday, Oct 1, 8:30 AM - 9:30 AMThere are many implementations of JavaScript, meant to run either on the JVM or standalone as native code. Both approaches have their respective pros and cons. The Oracle Nashorn JavaScript project is based on the former approach. This presentation goes through the performance work that has gone on in Oracle’s Nashorn JavaScript project to date in order to make JavaScript-to-bytecode generation for execution on the JVM feasible. It shows that the new invoke dynamic bytecode gets us part of the way there but may not quite be enough. What other tricks did the Nashorn project use? The presentation also discusses future directions for increased performance for dynamic languages on the JVM, covering proposed enhancements to both the JVM itself and to the bytecode compiler.CON4082 - Nashorn: JavaScript on the JVM - Monday, Oct 1, 3:00 PM - 4:00 PMThe JavaScript programming language has been experiencing a renaissance of late, driven by the interest in HTML5. Nashorn is a JavaScript engine implemented fully in Java on the JVM. It is based on the Da Vinci Machine (JSR 292) and will be available with JDK 8. This session describes the goals of Project Nashorn, gives a top-level view of how it all works, provides the current status, and demonstrates examples of JavaScript and Java working together.BOF4763 - Meet the Nashorn JavaScript Team - Tuesday, Oct 2, 4:30 PM - 5:15 PMCome to this session to meet the Oracle JavaScript (Project Nashorn) language teamBOF6661 - Nashorn, Node, and Java Persistence - Tuesday, Oct 2, 5:30 PM - 6:15 PMWith Project Nashorn, developers will have a full and modern JavaScript engine available on the JVM. In addition, they will have support for running Node applications with Node.jar. This unique combination of capabilities opens the door for best-of-breed applications combining Node with Java SE and Java EE. In this session, you’ll learn about Node.jar and how it can be combined with Java EE components such as EclipseLink JPA for rich Java persistence. You’ll also hear about all of Node.jar’s mapping, caching, querying, performance, and scaling features.CON10657 - The Polyglot Java VM and Java Middleware - Thursday, Oct 4, 12:30 PM - 1:30 PMIn this session, Red Hat and Oracle discuss the impact of polyglot programming from their own unique perspectives, examining non-Java languages that utilize Oracle’s Java HotSpot VM. You’ll hear a discussion of topics relating to Ruby, Lisp, and Clojure and the intersection of other languages where they may touch upon individual frameworks and projects, and you’ll get perspectives on JavaScript via the Nashorn Project, an upcoming JavaScript engine, developed fully in Java.CON5251 - Putting the Metaobject Protocol to Work: Nashorn’s Java Bindings - Thursday, Oct 4, 2:00 PM - 3:00 PMProject Nashorn is Oracle’s new JavaScript runtime in Java 8. Being a JavaScript runtime running on the JVM, it provides integration with the underlying runtime by enabling JavaScript objects to manipulate Java objects, implement Java interfaces, and extend Java classes. Nashorn is invokedynamic-based, and for its Java integration, it does away with the concept of wrapper objects in favor of direct virtual machine linking to Java objects’ methods provided by a metaobject protocol, providing much higher performance than what could be expected from a scripting runtime. This session looks at the details of the integration, a topic of interest to other language implementers on the JVM and a wider audience of developers who want to understand how Nashorn works.That's 6 sessions tooting the Nashorn this year at JavaOne, up from 2 last year.

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• ARTS Reference Model for Retail

  - by Sanjeev Sharma

  Consider a hypothetical scenario where you have been tasked to set up retail operations for a electronic goods or daily consumables or a luxury brand etc. It is very likely you will be faced with the following questions: What are the essential business capabilities that you must have in place?  What are the essential business activities under-pinning each of the business capabilities, identified in Step 1? What are the set of steps that you need to perform to execute each of the business activities, identified in Step 2? Answers to the above will drive your investments in software and hardware to enable the core retail operations. More importantly, the choices you make in responding to the above questions will several implications in the short-run and in the long-run. In the short-term, you will incur the time and cost of defining your technology requirements, procuring the software/hardware components and getting them up and running. In the long-term, as you grow in operations organically or through M&A, partnerships and franchiser business models  you will invariably need to make more technology investments to manage the greater complexity (scale and scope) of business operations.  "As new software applications, such as time & attendance, labor scheduling, and POS transactions, just to mention a few, are introduced into the store environment, it takes a disproportionate amount of time and effort to integrate them with existing store applications. These integration projects can add up to 50 percent to the time needed to implement a new software application and contribute significantly to the cost of the overall project, particularly if a systems integrator is called in. This has been the reality that all retailers have had to live with over the last two decades. The effect of the environment has not only been to increase costs, but also to limit retailers' ability to implement change and the speed with which they can do so." (excerpt taken from here) Now, one would think a lot of retailers would have already gone through the pain of finding answers to these questions, so why re-invent the wheel? Precisely so, a major effort began almost 17 years ago in the retail industry to make it less expensive and less difficult to deploy new technology in stores and at the retail enterprise level. This effort is called the Association for Retail Technology Standards (ARTS). Without standards such as those defined by ARTS, you would very likely end up experiencing the following: Increased Time and Cost due to resource wastage arising from re-inventing the wheel i.e. re-creating vanilla processes from scratch, and incurring, otherwise avoidable, mistakes and errors by ignoring experience of others Sub-optimal Process Efficiency due to narrow, isolated view of processes thereby ignoring process inter-dependencies i.e. optimizing parts but not the whole, and resulting in lack of transparency and inter-departmental finger-pointing Embracing ARTS standards as a blue-print for establishing or managing or streamlining your retail operations can benefit you in the following ways: Improved Time-to-Market from parity with industry best-practice processes e.g. ARTS, thus avoiding “reinventing the wheel” for common retail processes and focusing more on customizing processes for differentiations, and lowering integration complexity and risk with a standardized vocabulary for exchange between internal and external i.e. partner systems Lower Operating Costs by embracing the ARTS enterprise-wide process reference model for developing and streamlining retail operations holistically instead of a narrow, silo-ed view, and  procuring IT systems in compliance with ARTS thus avoiding IT budget marginalization While parity with industry standards such as ARTS business process model by itself does not create a differentiation, it does however provide a higher starting point for bridging the strategy-execution gap in setting up and improving retail operations.

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• Looking for a real-world example illustrating that composition can be superior to inheritance

  - by Job

  I watched a bunch of lectures on Clojure and functional programming by Rich Hickey as well as some of the SICP lectures, and I am sold on many concepts of functional programming. I incorporated some of them into my C# code at a previous job, and luckily it was easy to write C# code in a more functional style. At my new job we use Python and multiple inheritance is all the rage. My co-workers are very smart but they have to produce code fast given the nature of the company. I am learning both the tools and the codebase, but the architecture itself slows me down as well. I have not written the existing class hierarchy (neither would I be able to remember everything about it), and so, when I started adding a fairly small feature, I realized that I had to read a lot of code in the process. At the surface the code is neatly organized and split into small functions/methods and not copy-paste-repetitive, but the flip side of being not repetitive is that there is some magic functionality hidden somewhere in the hierarchy chain that magically glues things together and does work on my behalf, but it is very hard to find and follow. I had to fire up a profiler and run it through several examples and plot the execution graph as well as step through a debugger a few times, search the code for some substring and just read pages at the time. I am pretty sure that once I am done, my resulting code will be short and neatly organized, and yet not very readable. What I write feels declarative, as if I was writing an XML file that drives some other magic engine, except that there is no clear documentation on what the XML should look like and what the engine does except for the existing examples that I can read as well as the source code for the 'engine'. There has got to be a better way. IMO using composition over inheritance can help quite a bit. That way the computation will be linear rather than jumping all over the hierarchy tree. Whenever the functionality does not quite fit into an inheritance model, it will need to be mangled to fit in, or the entire inheritance hierarchy will need to be refactored/rebalanced, sort of like an unbalanced binary tree needs reshuffling from time to time in order to improve the average seek time. As I mentioned before, my co-workers are very smart; they just have been doing things a certain way and probably have an ability to hold a lot of unrelated crap in their head at once. I want to convince them to give composition and functional as opposed to OOP approach a try. To do that, I need to find some very good material. I do not think that a SCIP lecture or one by Rich Hickey will do - I am afraid it will be flagged down as too academic. Then, simple examples of Dog and Frog and AddressBook classes do not really connivence one way or the other - they show how inheritance can be converted to composition but not why it is truly and objectively better. What I am looking for is some real-world example of code that has been written with a lot of inheritance, then hit a wall and re-written in a different style that uses composition. Perhaps there is a blog or a chapter. I am looking for something that can summarize and illustrate the sort of pain that I am going through. I already have been throwing the phrase "composition over inheritance" around, but it was not received as enthusiastically as I had hoped. I do not want to be perceived as a new guy who likes to complain and bash existing code while looking for a perfect approach while not contributing fast enough. At the same time, my gut is convinced that inheritance is often the instrument of evil and I want to show a better way in a near future. Have you stumbled upon any great resources that can help me?

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• C# 5 Async, Part 3: Preparing Existing code For Await

  - by Reed

  While the Visual Studio Async CTP provides a fantastic model for asynchronous programming, it requires code to be implemented in terms of Task and Task<T>.  The CTP adds support for Task-based asynchrony to the .NET Framework methods, and promises to have these implemented directly in the framework in the future.  However, existing code outside the framework will need to be converted to using the Task class prior to being usable via the CTP. Wrapping existing asynchronous code into a Task or Task<T> is, thankfully, fairly straightforward.  There are two main approaches to this. Code written using the Asynchronous Programming Model (APM) is very easy to convert to using Task<T>.  The TaskFactory class provides the tools to directly convert APM code into a method returning a Task<T>.  This is done via the FromAsync method.  This method takes the BeginOperation and EndOperation methods, as well as any parameters and state objects as arguments, and returns a Task<T> directly. For example, we could easily convert the WebRequest BeginGetResponse and EndGetResponse methods into a method which returns a Task<WebResponse> via: Task<WebResponse> task = Task.Factory .FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Event-based Asynchronous Pattern (EAP) code can also be wrapped into a Task<T>, though this requires a bit more effort than the one line of code above.  This is handled via the TaskCompletionSource<T> class.  MSDN provides a detailed example of using this to wrap an EAP operation into a method returning Task<T>.  It demonstrates handling cancellation and exception handling as well as the basic operation of the asynchronous method itself. The basic form of this operation is typically: Task<YourResult> GetResultAsync() { var tcs = new TaskCompletionSource<YourResult>(); // Handle the event, and setup the task results... this.GetResultCompleted += (o,e) => { if (e.Error != null) tcs.TrySetException(e.Error); else if (e.Cancelled) tcs.TrySetCanceled(); else tcs.TrySetResult(e.Result); }; // Call the asynchronous method this.GetResult(); // Return the task from the TaskCompletionSource return tcs.Task; } We can easily use these methods to wrap our own code into a method that returns a Task<T>.  Existing libraries which cannot be edited can be extended via Extension methods.  The CTP uses this technique to add appropriate methods throughout the framework. The suggested naming for these methods is to define these methods as “Task<YourResult> YourClass.YourOperationAsync(…)”.  However, this naming often conflicts with the default naming of the EAP.  If this is the case, the CTP has standardized on using “Task<YourResult> YourClass.YourOperationTaskAsync(…)”. Once we’ve wrapped all of our existing code into operations that return Task<T>, we can begin investigating how the Async CTP can be used with our own code.

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• Introduction to WebCenter Personalization: &ldquo;The Conductor&rdquo;

  - by Steve Pepper

  There are some new faces in the town of WebCenter with the latest 11g PS3 release.  A new component has introduced itself as "Oracle WebCenter Personalization", a.k.a WCP, to simplify delivery of a personalized experience and content to end users.  This posting reviews one of the primary components within WCP: "The Conductor". The Conductor: This ain't just an ordinary cloud... One of the founding principals behind WebCenter Personalization was to provide an open client-side API that remains independent of the technology invoking it, in addition to independence from the architecture running it.  The Conductor delivers this, and much, much more. The Conductor is the engine behind WebCenter Personalization that allows flow-based documents, called "Scenarios", to be managed and executed on the server-side through a well published and RESTful api.      The Conductor also supports an extensible model for custom provider integration that can be easily invoked within a Scenario to promote seamless integration with existing business assets. Introducing the Scenario Conductor Scenarios are declarative offline-authored documents using the custom Personalization JDeveloper bundle included with WebCenter.  A Scenario contains one (or more) statements that can: Create variables that are scoped to the current execution context Iterate over collections, or loop until a specific condition is met Execute one or more statements when a condition is met Invoke other scenarios that exist within the same namespace Invoke a data provider that integrates with custom applications Once a variable is assigned within the Scenario's execution context, it can be referenced anywhere within the same Scenario using the common Expression Language syntax used in J2EE web containers. Scenarios are then published and tested to the Integrated WebLogic Server domain, or published remotely to other domains running WebCenter Personalization. Various Client-side Models The Conductor server API is built upon RESTful services that support a wide variety of clients able to communicate over HTTP.  The Conductor supports the following client-side models: REST:  Popular browser-based languages can be used to manage and execute Conductor Scenarios.  There are other public methods to retrieve configured provider metadata that can be used by custom applications. The Conductor currently supports XML and JSON for it's API syntax. Java: WebCenter Personalization delivers a robust and light-weight java client with the popular Jersey framework as it's foundation.  It has never been easier to write a remote java client to manage remote RESTful services. Expression Language (EL): Allow the results of Scenario execution to control your user interface or embed personalized content using the session-scoped managed bean.  The EL client can also be used in straight JSP pages with minimal configuration. Extensible Provider Framework The Conductor supports a pluggable provider framework for integrating custom code with Scenario execution.  There are two types of providers supported by the Conductor: Function Provider: Function Providers are simple java annotated classes with static methods that are meant to be served as utilities.  Some common uses would include: object creation or instantiation, data transformation, and the like.  Function Providers can be invoked using the common EL syntax from variable assignments, conditions, and loops. For example:  ${myUtilityClass:doStuff(arg1,arg2))} If you are familiar with EL Functions, Function Providers are based on the same concept. Data Provider: Like Function Providers, Data Providers are annotated java classes, but they must adhere to a much more strict object model.  Data Providers have access to a wealth of Conductor services, such as: Access to namespace-scoped configuration API that can be managed by Oracle Enterprise Manager, Scenario execution context for expression resolution, and more.  Oracle ships with three out-of-the-box data providers that supports integration with: Standardized Content Servers(CMIS),  Federated Profile Properties through the Properties Service, and WebCenter Activity Graph. Useful References If you are looking to immediately get started writing your own application using WebCenter Personalization Services, you will find the following references helpful in getting you on your way: Personalizing WebCenter Applications Authoring Personalized Scenarios in JDeveloper Using Personalization APIs Externally Implementing and Calling Function Providers Implementing and Calling Data Providers

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• Brazil is Hot for Social Media

  - by Mike Stiles

  Today’s guest blog is from Oracle SVP Product Development Reggie Bradford, fresh off a visit to Sao Paulo, Brazil where he spoke at the Dachis Social Business Summit and spent some time getting a personal taste for the astonishing growth of social in Brazil, both in terms of usage and engagement. I knew it was big, but I now have an all-new appreciation for why the Wall Street Journal branded Brazil the “social media capital of the universe.” Brazil has the world’s 5th largest economy, an expanding middle class, an active younger demo market, a connected & outgoing culture, and an ongoing embrace of the social media platforms. According to comScore's 2012 Brazil Digital Future in Focus report, 97% are using social media, and that’s not even taking mobile-only users into account. There were 65 million Facebook users in 2012, spending an average 535 minutes there, up 208%. It’s one of Twitter’s fastest growing markets and the 2nd biggest market for YouTube. Instagram usage has grown over 300% since last year. That by itself is exciting, but look at the opportunity for social marketing brands. 74% of Brazilian social users follow brands on Facebook, and 59% have praised a company on either Twitter or Facebook. A 2011 Oh! Panel study found 81% of social networkers there used social to research new products and 75% went there looking for discounts. B2C eCommerce sales in Brazil is projected to hit $26.9 billion by 2015. I bet I’m not the only one who sees great things ahead, and I was fortunate enough give a keynote ABRADI, an association of leading digital agencies in Brazil with 53 execs from 35 agencies attending. I was also afforded the opportunity to give my impressions of what’s going on in Brazil to Jornal Propoganda & Marketing, one of the most popular publications in Latin America for marketers. I conveyed that especially in an environment like Brazil, where social users are so willing to connect and engage brands, marketers need to back away from the heavy-handed, one-way messaging of old school advertising and move toward genuine relationships and trust-building. To aide in this, organizational and operation changes must be embraced inside the enterprise. We've talked often about the new, tighter partnership forming between the CIO and CMO. If this partnership is not encouraged, fostered and resourced, the increasing amount of time consumers spend on mobile and digital, and the efficiencies and integrations offered by cloud-based software cannot be exploited. These are the kinds of changes that can yield social data that, when combined with enterprise data, helps you come to know your social audiences intimately and predict their needs. Consumers are always connected and need your brand to be accessible at any time, be it for information or customer service. And, of course, all of this is happening quite publicly. The holistic, socially-enable enterprise connects social to customer service systems and all other customer touch points, facilitating the kind of immediate, real-time, gratifying response customers are coming to expect. Social users in Brazil are highly active and clearly willing to meet us as brands more than halfway. Empowering yourself with a social management technology platform will have you set up to maximize this booming social market…from listening & monitoring to engagement to analytics to workflow & automation to globalization & language support. Brands, it’s time to be as social as the great people of Brazil are. Obrigado! @reggiebradfordPhoto: Gualberto107, freedigitalphotos.net

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• Multithreading 2D gravity calculations

  - by Postman

  I'm building a space exploration game and I've currently started working on gravity ( In C# with XNA). The gravity still needs tweaking, but before I can do that, I need to address some performance issues with my physics calculations. This is using 100 objects, normally rendering 1000 of them with no physics calculations gets well over 300 FPS (which is my FPS cap), but any more than 10 or so objects brings the game (and the single thread it runs on) to its knees when doing physics calculations. I checked my thread usage and the first thread was killing itself from all the work, so I figured I just needed to do the physics calculation on another thread. However when I try to run the Gravity.cs class's Update method on another thread, even if Gravity's Update method has nothing in it, the game is still down to 2 FPS. Gravity.cs public void Update() { foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { Vector2 Force = new Vector2(); foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { if (e2.Key != e.Key) { float distance = Vector2.Distance(entityEngine.Entities[e.Key].Position, entityEngine.Entities[e2.Key].Position); if (distance > (entityEngine.Entities[e.Key].Texture.Width / 2 + entityEngine.Entities[e2.Key].Texture.Width / 2)) { double angle = Math.Atan2(entityEngine.Entities[e2.Key].Position.Y - entityEngine.Entities[e.Key].Position.Y, entityEngine.Entities[e2.Key].Position.X - entityEngine.Entities[e.Key].Position.X); float mult = 0.1f * (entityEngine.Entities[e.Key].Mass * entityEngine.Entities[e2.Key].Mass) / distance * distance; Vector2 VecForce = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle)); VecForce.Normalize(); Force = Vector2.Add(Force, VecForce * mult); } } } entityEngine.Entities[e.Key].Position += Force; } } Yeah, I know. It's a nested foreach loop, but I don't know how else to do the gravity calculation, and this seems to work, it's just so intensive that it needs its own thread. (Even if someone knows a super efficient way to do these calculations, I'd still like to know how I COULD do it on multiple threads instead) EntityEngine.cs (manages an instance of Gravity.cs) public class EntityEngine { public Dictionary<string, Entity> Entities = new Dictionary<string, Entity>(); public Gravity gravity; private Thread T; public EntityEngine() { gravity = new Gravity(this); } public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { Entities[e.Key].Update(); } T = new Thread(new ThreadStart(gravity.Update)); T.IsBackground = true; T.Start(); } } EntityEngine is created in Game1.cs, and its Update() method is called within Game1.cs. I need my physics calculation in Gravity.cs to run every time the game updates, in a separate thread so that the calculation doesn't slow the game down to horribly low (0-2) FPS. How would I go about making this threading work? (any suggestions for an improved Planetary Gravity system are welcome if anyone has them) I'm also not looking for a lesson in why I shouldn't use threading or the dangers of using it incorrectly, I'm looking for a straight answer on how to do it. I've already spent an hour googling this very question with little results that I understood or were helpful. I don't mean to come off rude, but it always seems hard as a programming noob to get a straight meaningful answer, I usually rather get an answer so complex I'd easily be able to solve my issue if I understood it, or someone saying why I shouldn't do what I want to do and offering no alternatives (that are helpful). Thank you for the help!

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• Passing data between the VirtualBox Host and the Guest

  - by Fat Bloke

  Here's a good question: "How can you figure out the VM name from within the VM itself?" While this data is not automatically available, the general purpose, and very powerful VirtualBox "GuestProperty" APIs can be used from the host and guest to pass arbitrary data, in key/value pairs format, in and out of the guest. Note that this does require that the VirtualBox Guest Additions have been installed in the guest. To play with this, try using the "VBoxManage" command line on your VirtualBox host machine, and "VBoxControl" in the guest. Host syntax VBoxManage guestproperty get <vmname>|<uuid> <property> [--verbose] VBoxManage guestproperty set <vmname>|<uuid> <property> [<value> [--flags <flags>]] VBoxManage guestproperty enumerate <vmname>|<uuid> [--patterns <patterns>] VBoxManage guestproperty wait <vmname>|<uuid> <patterns> [--timeout <msec>] [--fail-on-timeout]   Guest syntax VBoxControl.exe guestproperty        get <property> [-verbose] VBoxControl.exe guestproperty        set <property> [<value> [-flags <flags>]] VBoxControl.exe guestproperty        enumerate [-patterns <patterns>] VBoxControl.exe guestproperty        wait <patterns>                                      [-timestamp <last timestamp>]                                      [-timeout <timeout in ms>  So to solve our problem above, we set the vm name in the Host system on an arbitrary key like this: $ VBoxManage guestproperty set "Windows 7 (x64)" /MyData/VMname "Windows 7 (x64)" And within the guest we can use: C:\Program Files\Oracle\VirtualBox Guest Additions>VBoxControl.exe guestproperty get /MyData/VMname Oracle VM VirtualBox Guest Additions Command Line Management Interface Version 4.1.14 (C) 2008-2012 Oracle Corporation All rights reserved. Value: Windows 7 (x64) The GuestProperty API is pretty powerful, so for the interested, get more info in the User Manual. - FB 

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• If the model is validating the data, shouldn't it throw exceptions on bad input?

  - by Carlos Campderrós

  Reading this SO question it seems that throwing exceptions for validating user input is frowned upon. But who should validate this data? In my applications, all validations are done in the business layer, because only the class itself really knows which values are valid for each one of its properties. If I were to copy the rules for validating a property to the controller, it is possible that the validation rules change and now there are two places where the modification should be made. Is my premise that validation should be done on the business layer wrong? What I do So my code usually ends up like this: <?php class Person { private $name; private $age; public function setName($n) { $n = trim($n); if (mb_strlen($n) == 0) { throw new ValidationException("Name cannot be empty"); } $this->name = $n; } public function setAge($a) { if (!is_int($a)) { if (!ctype_digit(trim($a))) { throw new ValidationException("Age $a is not valid"); } $a = (int)$a; } if ($a < 0 || $a > 150) { throw new ValidationException("Age $a is out of bounds"); } $this->age = $a; } // other getters, setters and methods } In the controller, I just pass the input data to the model, and catch thrown exceptions to show the error(s) to the user: <?php $person = new Person(); $errors = array(); // global try for all exceptions other than ValidationException try { // validation and process (if everything ok) try { $person->setAge($_POST['age']); } catch (ValidationException $e) { $errors['age'] = $e->getMessage(); } try { $person->setName($_POST['name']); } catch (ValidationException $e) { $errors['name'] = $e->getMessage(); } ... } catch (Exception $e) { // log the error, send 500 internal server error to the client // and finish the request } if (count($errors) == 0) { // process } else { showErrorsToUser($errors); } Is this a bad methodology? Alternate method Should maybe I create methods for isValidAge($a) that return true/false and then call them from the controller? <?php class Person { private $name; private $age; public function setName($n) { $n = trim($n); if ($this->isValidName($n)) { $this->name = $n; } else { throw new Exception("Invalid name"); } } public function setAge($a) { if ($this->isValidAge($a)) { $this->age = $a; } else { throw new Exception("Invalid age"); } } public function isValidName($n) { $n = trim($n); if (mb_strlen($n) == 0) { return false; } return true; } public function isValidAge($a) { if (!is_int($a)) { if (!ctype_digit(trim($a))) { return false; } $a = (int)$a; } if ($a < 0 || $a > 150) { return false; } return true; } // other getters, setters and methods } And the controller will be basically the same, just instead of try/catch there are now if/else: <?php $person = new Person(); $errors = array(); if ($person->isValidAge($age)) { $person->setAge($age); } catch (Exception $e) { $errors['age'] = "Invalid age"; } if ($person->isValidName($name)) { $person->setName($name); } catch (Exception $e) { $errors['name'] = "Invalid name"; } ... if (count($errors) == 0) { // process } else { showErrorsToUser($errors); } So, what should I do? I'm pretty happy with my original method, and my colleagues to whom I have showed it in general have liked it. Despite this, should I change to the alternate method? Or am I doing this terribly wrong and I should look for another way?

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• My architecture has a problem with views that required information from different objects. How can I solve this?

  - by Oscar

  I am building an architecture like this: These are my SW layers ______________ | | | Views | |______________| ______________ | | |Business Logic| |______________| ______________ | | | Repository | |______________| My views are going to generate my HTML to be sent to the user Business logic is where all the business logics are Repository is a layer to access the DB My idea is that the repository uses entities (that are basically the representation of the tables, in order to perform DB queries. The layers communicate between themselves using Business Objects, that are objects that represent the real-world-object itself. They can contain business rules and methods. The views build/use DTOs, they are basically objects that have the information required to be shown on the screen. They expect also this kind of object on actions and, before calling the business logic, they create BO. First question: what is your overall feeling about this architecture? I've used similar architecture for some projects and I always got this problem: If my view has this list to show : Student1, age, course, Date Enrolled, Already paid? It has information from different BO. How do you think one should build the structure? These were the alternatives I could think of: The view layer could call the methods to get the student, then the course it studies, then the payment information. This would cause a lot of DB accesses and my view would have the knowledge about how to act to generate this information. This just seems wrong for me. I could have an "adapter object", that has the required information (a class that would have a properties Student, Course and Payment). But I would required one adapter object for each similar case, this may get very bad for big projects. I still don't like them. Would you have ideas? How would you change the architecture to avoid this kind of problems? @Rory: I read the CQRS and I don't think this suits my needs. As taken from a link references in your link Before describing the details of CQRS we need to understand the two main driving forces behind it: collaboration and staleness That means: many different actors using the same object (collaboration) and once data has been shown to a user, that same data may have been changed by another actor – it is stale (staleness). My problem is that I want to show to the user information from different BO, so I would need to receive them from the service layer. How can my service layer assemble and deliver this information? Edit to @AndrewM: Yes, you understood it correctly, the original idea was to have the view layer to build the BOs, but you have a very nice point about the creation of the BO inside the business layers. Assuming I follow your advice and move the creation logic inside the business layer, my business layer interface would contain the DTOs, for instance public void foo(MyDTO object) But as far as I understand, the DTO is tightly coupled to each view, so it would not be reusable by a second view. In order to use it, the second view would need to build a specific DTO from a specific view or I would have to duplicate the code in the business layer. Is this correct or am I missing something?

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• Wireless device bug on 13.10. BCM4313 registers as eth1 instead of wlan0 and no internet access

  - by user205691

  My Hotel wiFi requires me to login with a username & password after connecting to the hotspot. So, my browser would open a page with username & passwrd fields to login and then connect to internet. But unfortunately, firefox & chromium dont seem to work. i dont think it is browser related but a setting for the wifi router or driver which is creating this issue. using Broadcom 801.11 STA wireless driver (proprietary). tried open source as well but same result !! The image linked below shows my wifi connection setting & Chromium. The login page itself comes up after a long time and after entering the credentials, it keeps loading for ever !! it is the same case for every other browser.. so i dont think its browser issue but something to do with wifi setting or network manager stuff.. interestingly, i am able to connect to WiFi networks with WPA key without any issue. Adhoc hotspot is a problem and that is my regular home network :( .. I hope i can get some help solving this issue ! I have tried repeating the same hotspot after login from my android, by creating a virtual repeater with WPA key and it works. I can browse on ubuntu using this method.. but cant be doing this regularly ! I tried loading the same login page of the hotel wifi while browsing through my repeater wifi created on mobile and screen shot attached below. the page loads up quick and easy.. so this means something is wrong with the way network manager handles adhoc connectivity & login ?? i installed wicd0 but it crashes on startup and not helpful at all ! Screenshot of Chromium page Login page with repeated hotspot ifconfig in my terminal results: krishna@krishna-HP-ENVY-4-Notebook-PC:~$ ifconfig eth0 Link encap:Ethernet HWaddr 28:92:4a:1d:54:fa UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr e0:06:e6:89:fa:49 inet addr:10.24.1.71 Bcast:10.24.1.255 Mask:255.255.255.0 inet6 addr: fe80::e206:e6ff:fe89:fa49/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:10940 errors:0 dropped:0 overruns:0 frame:348431 TX packets:6611 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:7669631 (7.6 MB) TX bytes:864195 (864.1 KB) Interrupt:17 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:2146 errors:0 dropped:0 overruns:0 frame:0 TX packets:2146 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:166120 (166.1 KB) TX bytes:166120 (166.1 KB) I wonder why is the wireless configured under eth1 ? I think this is a bug with earlier ubuntu versions, but is this normal in 13.10 or is there a wrong configuration here ? The wireless device in my pc is BCM4313 and i have installed the bcmwl-kernel-sources, wireless-tools to support the device. i also reinstalled the bcmwl-kernel as suggested on broadcom website, via synaptic package manager. Nothing has changed this situation ! I tried booting into liveUSB and then ifconfig results show wireless under wlan0. But then the wireless connects and loads the login page. So is the problem with the device configuration now ? i really want to get this fixed before i start configuring the other stuff like ATI graphics and such on the laptop for overheating.. lack of internet access is too bad a bug for me :P any help is appreciated!

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• Parameterized StreamInsight Queries

  - by Roman Schindlauer

  The changes in our APIs enable a set of scenarios that were either not possible before or could only be achieved through workarounds. One such use case that people ask about frequently is the ability to parameterize a query and instantiate it with different values instead of re-deploying the entire statement. I’ll demonstrate how to do this in StreamInsight 2.1 and combine it with a method of using subjects for dynamic query composition in a mini-series of (at least) two blog articles. Let’s start with something really simple: I want to deploy a windowed aggregate to a StreamInsight server, and later use it with different window sizes. The LINQ statement for such an aggregate is very straightforward and familiar: var result = from win in stream.TumblingWindow(TimeSpan.FromSeconds(5))               select win.Avg(e => e.Value); Obviously, we had to use an existing input stream object as well as a concrete TimeSpan value. If we want to be able to re-use this construct, we can define it as a IQStreamable: var avg = myApp     .DefineStreamable((IQStreamable<SourcePayload> s, TimeSpan w) =>         from win in s.TumblingWindow(w)         select win.Avg(e => e.Value)); The DefineStreamable API lets us define a function, in our case from a IQStreamable (the input stream) and a TimeSpan (the window length) to an IQStreamable (the result). We can then use it like a function, with the input stream and the window length as parameters: var result = avg(stream, TimeSpan.FromSeconds(5)); Nice, but you might ask: what does this save me, except from writing my own extension method? Well, in addition to defining the IQStreamable function, you can actually deploy it to the server, to make it re-usable by another process! When we deploy an artifact in V2.1, we give it a name: var avg = myApp     .DefineStreamable((IQStreamable<SourcePayload> s, TimeSpan w) =>         from win in s.TumblingWindow(w)         select win.Avg(e => e.Value))     .Deploy("AverageQuery"); When connected to the same server, we can now use that name to retrieve the IQStreamable and use it with our own parameters: var averageQuery = myApp     .GetStreamable<IQStreamable<SourcePayload>, TimeSpan, double>("AverageQuery"); var result = averageQuery(stream, TimeSpan.FromSeconds(5)); Convenient, isn’t it? Keep in mind that, even though the function “AverageQuery” is deployed to the server, its logic will still be instantiated into each process when the process is created. The advantage here is being able to deploy that function, so another client who wants to use it doesn’t need to ask the author for the code or assembly, but just needs to know the name of deployed entity. A few words on the function signature of GetStreamable: the last type parameter (here: double) is the payload type of the result, not the actual result stream’s type itself. The returned object is a function from IQStreamable<SourcePayload> and TimeSpan to IQStreamable<double>. In the next article we will integrate this usage of IQStreamables with Subjects in StreamInsight, so stay tuned! Regards, The StreamInsight Team

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• concurrency::extent<N> from amp.h

  - by Daniel Moth

  Overview We saw in a previous post how index<N> represents a point in N-dimensional space and in this post we'll see how to define the N-dimensional space itself. With C++ AMP, an N-dimensional space can be specified with the template class extent<N> where you define the size of each dimension. From a look and feel perspective, you'd expect the programmatic interface of a point type and size type to be similar (even though the concepts are different). Indeed, exactly like index<N>, extent<N> is essentially a coordinate vector of N integers ordered from most- to least- significant, BUT each integer represents the size for that dimension (and hence cannot be negative). So, if you read the description of index, you won't be surprised with the below description of extent<N> There is the rank field returning the value of N you passed as the template parameter. You can construct one extent from another (via the copy constructor or the assignment operator), you can construct it by passing an integer array, or via convenience constructor overloads for 1- 2- and 3- dimension extents. Note that the parameterless constructor creates an extent of the specified rank with all bounds initialized to 0. You can access the components of the extent through the subscript operator (passing it an integer). You can perform some arithmetic operations between extent objects through operator overloading, i.e. ==, !=, +=, -=, +, -. There are operator overloads so that you can perform operations between an extent and an integer: -- (pre- and post- decrement), ++ (pre- and post- increment), %=, *=, /=, +=, –= and, finally, there are additional overloads for plus and minus (+,-) between extent<N> and index<N> objects, returning a new extent object as the result. In addition to the usual suspects, extent offers a contains function that tests if an index is within the bounds of the extent (assuming an origin of zero). It also has a size function that returns the total linear size of this extent<N> in units of elements. Example code extent<2> e(3, 4); _ASSERT(e.rank == 2); _ASSERT(e.size() == 3 * 4); e += 3; e[1] += 6; e = e + index<2>(3,-4); _ASSERT(e == extent<2>(9, 9)); _ASSERT( e.contains(index<2>(8, 8))); _ASSERT(!e.contains(index<2>(8, 9))); grid<N> Our upcoming pre-release bits also have a similar type to extent, grid<N>. The way you create a grid is by passing it an extent, e.g. extent<3> e(4,2,6); grid<3> g(e); I am not going to dive deeper into grid, suffice for now to think of grid<N> simply as an alias for the extent<N> object, that you create when you encounter a function that expects a grid object instead of an extent object. Usage The extent class on its own simply defines the size of the N-dimensional space. We'll see in future posts that when you create containers (arrays) and wrappers (array_views) for your data, it is an extent<N> object that you'll need to use to create those (and use an index<N> object to index into them). We'll also see that it is a grid<N> object that you pass to the new parallel_for_each function that I'll cover in the next post. Comments about this post by Daniel Moth welcome at the original blog.

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• Inside Red Gate - Exercising Externally

  - by simonc

  Over the next few weeks, we'll be performing experiments on SmartAssembly to confirm or refute various hypotheses we have about how people use the product, what is stopping them from using it to its full extent, and what we can change to make it more useful and easier to use. Some of these experiments can be done within the team, some within Red Gate, and some need to be done on external users. External testing Some external testing can be done by standard usability tests and surveys, however, there are some hypotheses that can only be tested by building a version of SmartAssembly with some things in the UI or implementation changed. We'll then be able to look at how the experimental build is used compared to the 'mainline' build, which forms our baseline or control group, and use this data to confirm or refute the relevant hypotheses. However, there are several issues we need to consider before running experiments using separate builds: Ideally, the user wouldn't know they're running an experimental SmartAssembly. We don't want users to use the experimental build like it's an experimental build, we want them to use it like it's the real mainline build. Only then will we get valid, useful, and informative data concerning our hypotheses. There's no point running the experiments if we can't find out what happens after the download. To confirm or refute some of our hypotheses, we need to find out how the tool is used once it is installed. Fortunately, we've applied feature usage reporting to the SmartAssembly codebase itself to provide us with that information. Of course, this then makes the experimental data conditional on the user agreeing to send that data back to us in the first place. Unfortunately, even though this does limit the amount of useful data we'll be getting back, and possibly skew the data, there's not much we can do about this; we don't collect feature usage data without the user's consent. Looks like we'll simply have to live with this. What if the user tries to buy the experiment? This is something that isn't really covered by the Lean Startup book; how do you support users who give you money for an experiment? If the experiment is a new feature, and the user buys a license for SmartAssembly based on that feature, then what do we do if we later decide to pivot & scrap that feature? We've either got to spend time and money bringing that feature up to production quality and into the mainline anyway, or we've got disgruntled customers. Either way is bad. Again, there's not really any good solution to this. Similarly, what if we've removed some features for an experiment and a potential new user downloads the experimental build? (As I said above, there's no indication the build is an experimental build, as we want to see what users really do with it). The crucial feature they need is missing, causing a bad trial experience, a lost potential customer, and a lost chance to help the customer with their problem. Again, this is something not really covered by the Lean Startup book, and something that doesn't have a good solution. So, some tricky issues there, not all of them with nice easy answers. Turns out the practicalities of running Lean Startup experiments are more complicated than they first seem! Cross posted from Simple Talk.

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• New PeopleSoft HCM 9.1 On Demand Standard Edition provides a complete set of IT services at a low, predictable monthly cost

  - by Robbin Velayedam

  At Oracle Open World last month, Oracle announced that we are extending our On Demand offerings with the general availability of PeopleSoft On Demand Standard Edition. Standard Edition represents Oracle’s commitment to providing customers a choice of solutions, technology, and deployment options commensurate with their business needs and future growth. The Standard Edition offering complements the traditional On Demand offerings (Enterprise and Professional Editions) by focusing on a low, predictable monthly cost model that scales with the size of your business.   As part of Oracle's open cloud strategy, customers can freely move PeopleSoft licensed applications between on premise and the various  on demand options as business needs arise.    In today’s business climate, aggressive and creative business objectives demand more of IT organizations. They are expected to provide technology-based solutions to streamline business processes, enable online collaboration and multi-tasking, facilitate data mining and storage, and enhance worker productivity. As IT budgets remain tight in a recovering economy, the challenge becomes how to meet these demands with limited time and resources. One way is to eliminate the variable costs of projects so that your team can focus on the high priority functions and better predict funding and resource needs two to three years out. Variable costs and changing priorities can derail the best laid project and capacity plans. The prime culprits of variable costs in any IT organization include disaster recovery, security breaches, technical support, and changes in business growth and priorities. Customers have an immediate need for solutions that are cheaper, predictable in cost, and flexible enough for long-term growth or capacity changes. The Standard Edition deployment option fulfills that need by allowing customers to take full advantage of the rich business functionality that is inherent to PeopleSoft HCM, while delegating all application management responsibility – such as future upgrades and product updates – to Oracle technology experts, at an affordable and expected price. Standard Edition provides the advantages of the secure Oracle On Demand hosted environment, the complete set of PeopleSoft HCM configurable business processes, and timely management of regular updates and enhancements to the application functionality and underlying technology. Standard Edition has a convenient monthly fee that is scalable by number of employees, which helps align the customer’s overall cost of ownership with its size and anticipated growth and business needs. In addition to providing PeopleSoft HCM applications' world class business functionality and Oracle On Demand's embassy-grade security, Oracle’s hosted solution distinguishes itself from competitors by offering customers the ability to transition between different deployment and service models at any point in the application ownership lifecycle. As our customers’ business and economic climates change, they are free to transition their applications back to on-premise at any time. HCM On Demand Standard Edition is based on configurability options rather than customizations, requiring no additional code to develop or maintain. This keeps the cost of ownership low and time to production less than a month on average. Oracle On Demand offers the highest standard of security and performance by leveraging a state-of-the-art data center with dedicated databases, servers, and secured URL all within a private cloud. Customers will not share databases, environments, platforms, or access portals with other customers because we value how mission critical your data are to your business. Oracle’s On Demand also provides a full breadth of disaster recovery services to provide customers the peace of mind that their data are secure and that backup operations are in place to keep their businesses up and running in the case of an emergency. Currently we have over 50 PeopleSoft customers delegating us with the management of their applications through Oracle On Demand. If you are a customer interested in learning more about the PeopleSoft HCM 9.1 Standard Edition and how it can help your organization minimize your variable IT costs and free up your resources to work on other business initiatives, contact Oracle or your Account Services Representative today.

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• The Growing Importance of Network Virtualization

  - by user12608550

  The Growing Importance of Network Virtualization We often focus on server virtualization when we discuss cloud computing, but just as often we neglect to consider some of the critical implications of that technology. The ability to create virtual environments (or VEs [1]) means that we can create, destroy, activate and deactivate, and more importantly, MOVE them around within the cloud infrastructure. This elasticity and mobility has profound implications for how network services are defined, managed, and used to provide cloud services. It's not just servers that benefit from virtualization, it's the network as well. Network virtualization is becoming a hot topic, and not just for discussion but for companies like Oracle and others who have recently acquired net virtualization companies [2,3]. But even before this topic became so prominent, Solaris engineers were working on technologies in Solaris 11 to virtualize network services, known as Project Crossbow [4]. And why is network virtualization so important? Because old assumptions about network devices, topology, and management must be re-examined in light of the self-service, elasticity, and resource sharing requirements of cloud computing infrastructures. Static, hierarchical network designs, and inter-system traffic flows, need to be reconsidered and quite likely re-architected to take advantage of new features like virtual NICs and switches, bandwidth control, load balancing, and traffic isolation. For example, traditional multi-tier Web services (Web server, App server, DB server) that share net traffic over Ethernet wires can now be virtualized and hosted on shared-resource systems that communicate within a larger server at system bus speeds, increasing performance and reducing wired network traffic. And virtualized traffic flows can be monitored and adjusted as needed to optimize network performance for dynamically changing cloud workloads. Additionally, as VEs come and go and move around in the cloud, static network configuration methods cannot easily accommodate the routing and addressing flexibility that VE mobility implies; virtualizing the network itself is a requirement. Oracle Solaris 11 [5] includes key network virtualization technologies needed to implement cloud computing infrastructures. It includes features for the creation and management of virtual NICs and switches, and for the allocation and control of the traffic flows among VEs [6]. Additionally it allows for both sharing and dedication of hardware components to network tasks, such as allocating specific CPUs and vNICs to VEs, and even protocol-specific management of traffic. So, have a look at your current network topology and management practices in view of evolving cloud computing technologies. And don't simply duplicate the physical architecture of servers and connections in a virtualized environment…rethink the traffic flows among VEs and how they can be optimized using Oracle Solaris 11 and other Oracle products and services. [1] I use the term "virtual environment" or VE here instead of the more commonly used "virtual machine" or VM, because not all virtualized operating system environments are full OS kernels under the control of a hypervisor…in other words, not all VEs are VMs. In particular, VEs include Oracle Solaris zones, as well as SPARC VMs (previously called LDoms), and x86-based Solaris and Linux VMs running under hypervisors such as OEL, Xen, KVM, or VMware. [2] Oracle follows VMware into network virtualization space with Xsigo purchase; http://www.mercurynews.com/business/ci_21191001/oracle-follows-vmware-into-network-virtualization-space-xsigo [3] Oracle Buys Xsigo; http://www.oracle.com/us/corporate/press/1721421 [4] Oracle Solaris 11 Networking Virtualization Technology, http://www.oracle.com/technetwork/server-storage/solaris11/technologies/networkvirtualization-312278.html [5] Oracle Solaris 11; http://www.oracle.com/us/products/servers-storage/solaris/solaris11/overview/index.html [6] For example, the Solaris 11 'dladm' command can be used to limit the bandwidth of a virtual NIC, as follows: dladm create-vnic -l net0 -p maxbw=100M vnic0

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