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• Five Best Practices for Going Mobile

  - by kellsey.ruppel

  76% of IT decision makers indicate mobile trends will have a high to extremely high impact on their organization. Has your organization gone mobile? Looking for some ideas on how to get started? John Brunswick shares his Best Practices for Going Mobile. Mobile technology has gone from nice-to-have to a cornerstone of user engagement. Mobile access enables social networking, decision support, purchasing, content consumption, and location-based searching, extending experiences beyond what is available in traditional desktop computing.  Organizations rushing to ensure their brand's mobile availability may have taken a tactical approach to implementation, but strategically approaching mobile can enable greater returns on a similar investment and subsequent mobile projects. Here are some strategic considerations for delivering products, services, and information to mobile constituents.  Who, Why, and What? Ask yourself these key questions: who are you attempting to engage through the channel, and why are they engaging you through this channel? What experience will satisfy their needs? What outcome will support your core business? Will you be informing and/or transacting with this person?  Mobile Behavior. Mobile users generally engage for a very specific purpose. Ensure that access to information, services, and products is streamlined. Arriving on a mobile site through search only to be asked to search again frustrates users.  Mobile Is Broad. After establishing the audience and goal, review technology requirements to support them. Do you need a mobile Website, native mobile application, or both? Do you need to support multiple devices? Know the difference between native mobile and mobile Web.  Social Strategy. Users are more likely to trust reviews from peers than marketing information from a vendor. If you are selling products or services, be sure to make social integration part of your strategy.  Content Management. Consider a shared content platform strategy for Web and mobile projects. Fresh, consistent content is important for high-quality experiences. Read more from John Brunswick.We'll also be talking mobile strategies and how you can transform your portal experience and optimize online engagement -- making your portals more interactive and more engaging across multiple channels in a webcast tomorrow. We hope you'll join us!

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• SCHA API for resource group failover / switchover history

  - by krishna.k.murthy

  The Oracle Solaris Cluster framework keeps an internal log of cluster events, including switchover and failover of resource groups. These logs can be useful to Oracle support engineers for diagnosing cluster behavior. However, till now, there was no external interface to access the event history. Oracle Solaris Cluster 4.2 provides a new API option for viewing the recent history of resource group switchovers in a program-parsable format. Oracle Solaris Cluster 4.2 provides a new option tag argument RG_FAILOVER_LOG for the existing API command scha_cluster_get which can be used to list recent failover / switchover events for resource groups. The command usage is as shown below: # scha_cluster_get -O RG_FAILOVER_LOG number_of_days number_of_days : the number of days to be considered for scanning the historical logs. The command returns a list of events in the following format. Each field is separated by a semi-colon [;]: resource_group_name;source_nodes;target_nodes;time_stamp source_nodes: node_names from which resource group is failed over or was switched manually. target_nodes: node_names to which the resource group failed over or was switched manually. There is a corresponding enhancement in the C API function scha_cluster_get() which uses the SCHA_RG_FAILOVER_LOG query tag. In the example below geo-infrastructure (failover resource group), geo-clusterstate (scalable resource group), oracle-rg (failover resource group), asm-dg-rg (scalable resource group) and asm-inst-rg (scalable resource group) are part of Geographic Edition setup. # /usr/cluster/bin/scha_cluster_get -O RG_FAILOVER_LOG 3 geo-infrastructure;schost1c;;Mon Jul 21 15:51:51 2014 geo-clusterstate;schost2c,schost1c;schost2c;Mon Jul 21 15:52:26 2014 oracle-rg;schost1c;;Mon Jul 21 15:54:31 2014 asm-dg-rg;schost2c,schost1c;schost2c;Mon Jul 21 15:54:58 2014 asm-inst-rg;schost2c,schost1c;schost2c;Mon Jul 21 15:56:11 2014 oracle-rg;;schost2c;Mon Jul 21 15:58:51 2014 geo-infrastructure;;schost2c;Mon Jul 21 15:59:19 2014 geo-clusterstate;schost2c;schost2c,schost1c;Mon Jul 21 16:01:51 2014 asm-inst-rg;schost2c;schost2c,schost1c;Mon Jul 21 16:01:10 2014 asm-dg-rg;schost2c;schost2c,schost1c;Mon Jul 21 16:02:10 2014 oracle-rg;schost2c;;Tue Jul 22 16:58:02 2014 oracle-rg;;schost1c;Tue Jul 22 16:59:05 2014 oracle-rg;schost1c;schost1c;Tue Jul 22 17:05:33 2014 Note that in the output some of the entries might have an empty string in the source_nodes. Such entries correspond to events in which the resource group is switched online manually or during a cluster boot-up. Similarly, an empty destination_nodes list indicates an event in which the resource group went offline. - Arpit Gupta, Harish Mallya

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• Updating My Online Boggle Solver Using jQuery Templates and WCF

  With WebForms, each ASP.NET page's rendered output includes a <form> element that performs a postback to the same page whenever a Button control within the form is clicked, or whenever the user modifies a control whose AutoPostBack property is set to True. This model simplifies web page development, but carries with it some costs - namely, the large amount of data exchanged between the client and the server during a postback. On postback the browser sends the values of all of its form fields (including hidden ones, like view state, which may be quite large) to the server; the server then sends back the entire contents of the web page. While there are some scenarios where this amount of information needs to be exchanged, in many cases the user has performed some action that requires far less information to be exchanged. With a little bit of forethought and code we can have the browser and server exchange much less data, which leads to more responsive web pages and an improved user experience. Over the past several weeks I've been writing an article series on accessing server-side data from client script. Rather than rely solely on forms and postbacks, many websites use JavaScript code to asynchronously communicate with the server in response to the page loading or some other user action. The server, upon receiving the JavaScript-initiated request, returns just the data needed by the browser, which the browser then seamlessly integrates into the web page. There are a variety of technologies and techniques that can be employed to provide both the needed server- and client-side functionality. Last week's article, Using WCF Services with jQuery and the ASP.NET Ajax Library, explored using the Windows Communication Foundation, or WCF, to serve data from the web server and showed how to consume such a service using both the ASP.NET Ajax Library and jQuery. In a previous 4Guys article, Creating an Online Boggle Solver, I built an application to find all solutions in a game of Boggle. (Boggle is a word game trademarked by Parker Brothers and Hasbro that involves several players trying to find as many words as they can in a 4x4 grid of letters.) This article takes the lessons learned in Using WCF Services with jQuery and the ASP.NET Ajax Library and uses them to update the user interface for my online Boggle solver, replacing the existing WebForms-based user interface with a more modern and responsive interface. I also used jQuery Templates, a JavaScript-based templating library that is useful for displaying the results from a server-side service. Read on to learn more! Read More >

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• Best Creational Pattern for loggers in a multi-threaded system?

  - by Dipan Mehta

  This is a follow up question on my past questions : Concurrency pattern of logger in multithreaded application As suggested by others, I am putting this question separately. As the learning from the last question. In a multi-threaded environment, the logger should be made thread safe and probably asynchronous (where in messages are queued while a background thread does writing releasing the requesting object thread). The logger could be signleton or it can be a per-group logger which is a generalization of the above. Now, the question that arise is how does logger should be assigned to the object? There are two options I can think of: 1. Object requesting for the logger: Should each of the object call some global API such as get_logger()? Such an API returns "the" singleton or the group logger. However, I feel this involves assumption about the Application environment to implement the logger -which I think is some kind of coupling. If the same object needs to be used by other application - this new application also need to implement such a method. 2. Assign logger through some known API The other alternative approach is to create a kind of virtual class which is implemented by application based on App's own structure and assign the object sometime in the constructor. This is more generalized method. Unfortunately, when there are so many objects - and rather a tree of objects passing on the logger objects to each level is quite messy. My question is there a better way to do this? If you need to pick any one of the above, which approach is would you pick and why? Other questions remain open about how to configure them: How do objects' names or ID are assigned so that will be used for printing on the log messages (as the module names) How do these objects find the appropriate properties (such as log levels, and other such parameters) In the first approach, the central API needs to deal with all this varieties. In the second approach - there needs to be additional work. Hence, I want to understand from the real experience of people, as to how to write logger effectively in such an environment.

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• Obtaining positional information in the IEnumerable Select extension method

  - by Kyle Burns

  This blog entry is intended to provide a narrow and brief look into a way to use the Select extension method that I had until recently overlooked. Every developer who is using IEnumerable extension methods to work with data has been exposed to the Select extension method, because it is a pretty critical piece of almost every query over a collection of objects.  The method is defined on type IEnumerable and takes as its argument a function that accepts an item from the collection and returns an object which will be an item within the returned collection.  This allows you to perform transformations on the source collection.  A somewhat contrived example would be the following code that transforms a collection of strings into a collection of anonymous objects: 1: var media = new[] {"book", "cd", "tape"}; 2: var transformed = media.Select( item => 3: { 4: Media = item 5: } ); This code transforms the array of strings into a collection of objects which each have a string property called Media. If every developer using the LINQ extension methods already knows this, why am I blogging about it?  I’m blogging about it because the method has another overload that I hadn’t seen before I needed it a few weeks back and I thought I would share a little about it with whoever happens upon my blog.  In the other overload, the function defined in the first overload as: 1: Func<TSource, TResult> is instead defined as: 1: Func<TSource, int, TResult>   The additional parameter is an integer representing the current element’s position in the enumerable sequence.  I used this information in what I thought was a pretty cool way to compare collections and I’ll probably blog about that sometime in the near future, but for now we’ll continue with the contrived example I’ve already started to keep things simple and show how this works.  The following code sample shows how the positional information could be used in an alternating color scenario.  I’m using a foreach loop because IEnumerable doesn’t have a ForEach extension, but many libraries do add the ForEach extension to IEnumerable so you can update the code if you’re using one of these libraries or have created your own. 1: var media = new[] {"book", "cd", "tape"}; 2: foreach (var result in media.Select( 3: (item, index) => 4: new { Item = item, Index = index })) 5: { 6: Console.ForegroundColor = result.Index % 2 == 0 7: ? ConsoleColor.Blue : ConsoleColor.Yellow; 8: Console.WriteLine(result.Item); 9: }

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• Need help fixing DPKG errors after update from 12.04 to 12.10

  - by James Wulfe

  So I was doing fine then i upgraded my system to 12.10 and now i cant get my system to update all of its packages properly. no matter what i do, what is happening here and how do i fix this. if i would have thought 12.10 would be this much of a hassle i would have never upgraded..... here is a sampling of the code that returns from "apt-get -f install" It should also be noted that it is just these 6 packages only. no other packages have given me this kind of trouble. well i should say as of now. It was just 5, but them i got an update for unity, and now unity-common is added to the trouble makers. which prevents me from further upgrading the actual unity package as this package is a dependancy. Preparing to replace usb-modeswitch-data 20120120-0ubuntu1 (using .../usb-modeswitch-data_20120815-1_all.deb) ... /var/lib/dpkg/info/usb-modeswitch-data.prerm: 4: /var/lib/dpkg/info/usb-modeswitch-data.prerm: dpkg-maintscript-helper: Input/output error dpkg: warning: subprocess old pre-removal script returned error exit status 2 dpkg: trying script from the new package instead ... /var/lib/dpkg/tmp.ci/prerm: 4: /var/lib/dpkg/tmp.ci/prerm: dpkg-maintscript-helper: Input/output error dpkg: error processing /var/cache/apt/archives/usb-modeswitch-data_20120815-1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 2 /var/lib/dpkg/info/usb-modeswitch-data.postinst: 7: /var/lib/dpkg/info/usb-modeswitch-data.postinst: dpkg-maintscript-helper: Input/output error dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 2 Errors were encountered while processing: /var/cache/apt/archives/network-manager_0.9.6.0-0ubuntu7_i386.deb /var/cache/apt/archives/pcmciautils_018-8_i386.deb /var/cache/apt/archives/unity-common_6.10.0-0ubuntu2_all.deb /var/cache/apt/archives/whoopsie_0.2.7_i386.deb /var/cache/apt/archives/usb-modeswitch_1.2.3+repack0-1ubuntu3_i386.deb /var/cache/apt/archives/usb-modeswitch-data_20120815-1_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1) I would also like to note i have cleaned apt cashe both through the terminal and manualy, i have tried installing them manually through dpkg from both the /var/cache/apt/archives/ location and from my own manually downloaded .deb files. i have tried using dpkg-reconfigure and i have used bleachbit to clean my system. I have also tested both my HDD and memory and found no significant errors to lead to the input/output errors. Quite frankly i am just out of options and have grown tired of trying to google a solution to this mess but still do not wish to pursue backing up settings and reinstalling the system. Any help would be appreciated. I am only interested in answers, please leave your feeling towards grammar, punctuation, and bias towards how a "post should look" at the door. If you dont have something to contribute towards solving my problem then you are just doing nothing but contributing to it. Thank you.

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• JavaScript Class Patterns &ndash; In CoffeeScript

  - by Liam McLennan

  Recently I wrote about JavaScript class patterns, and in particular, my favourite class pattern that uses closure to provide encapsulation. A class to represent a person, with a name and an age, looks like this: var Person = (function() { // private variables go here var name,age; function constructor(n, a) { name = n; age = a; } constructor.prototype = { toString: function() { return name + " is " + age + " years old."; } }; return constructor; })(); var john = new Person("John Galt", 50); console.log(john.toString()); Today I have been experimenting with coding for node.js in CoffeeScript. One of the first things I wanted to do was to try and implement my class pattern in CoffeeScript and then see how it compared to CoffeeScript’s built-in class keyword. The above Person class, implemented in CoffeeScript, looks like this: # JavaScript style class using closure to provide private methods Person = (() -> [name,age] = [{},{}] constructor = (n, a) -> [name,age] = [n,a] null constructor.prototype = toString: () -> "name is #{name} age is #{age} years old" constructor )() I am satisfied with how this came out, but there are a few nasty bits. To declare the two private variables in javascript is as simple as var name,age; but in CoffeeScript I have to assign a value, hence [name,age] = [{},{}]. The other major issue occurred because of CoffeeScript’s implicit function returns. The last statement in any function is returned, so I had to add null to the end of the constructor to get it to work. The great thing about the technique just presented is that it provides encapsulation ie the name and age variables are not visible outside of the Person class. CoffeeScript classes do not provide encapsulation, but they do provide nicer syntax. The Person class using native CoffeeScript classes is: # CoffeeScript style class using the class keyword class CoffeePerson constructor: (@name, @age) -> toString: () -> "name is #{@name} age is #{@age} years old" felix = new CoffeePerson "Felix Hoenikker", 63 console.log felix.toString() So now I have a trade-off: nice syntax against encapsulation. I think I will experiment with both strategies in my project and see which works out better.

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• Playing with F#

  - by mroberts

  Project Euler is a awesome site.   When working with a new language it can be tricky to find problems that need solving, that are more complex than "Hello World" and simpler than a full blown application. Project Euler gives use just that, cool and thought provoking problems that usually don't take days to solve.  I've solved a number of questions with C# and some with Java.  BTW, I used Java because it had BigInteger support before .Net. A couple weeks ago, back when winter had a firm grip on Columbus, OH, I began playing (researching) with F#.  I began with Problem #1 from Project Euler.  I started by looking at my solution in C#. Here is my solution in C#. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace Problem001 5: { 6: class Program 7: { 8: static void Main(string[] args) 9: { 10: List<int> values = new List<int>(); 11:   12: for (int i = 1; i < 1000; i++) 13: { 14: if (i % 3 == 0 || i % 5 == 0) 15: values.Add(i); 16: } 17: int total = 0; 18:   19: values.ForEach(v => total += v); 20:   21: Console.WriteLine(total); 22: Console.ReadKey(); 23: } 24: } 25: }   Now, after much tweaking and learning, here is my solution in F#.   1: open System 2:   3: let calc n = 4: [1..n] 5: |> List.map (fun x -> if (x % 3 = 0 || x % 5 = 0) then x else 0) 6: |> List.sum 7:   8: let main() = 9: calc 999 10: |> printfn "result = %d" 11: Console.ReadKey(true) |> ignore 12:   13: main() Just this little example highlights some cool things about F#. Type inference. F# infers the type of a value.  In the C# code above we declare a number of variables, the list, and a couple ints.  F# does not require this, it infers the calc (a function) accepts a int and returns a int. Great built in functionality for Lists.  List.map for example. BTW, I don’t think I’m spilling the beans by giving away the code for Problem 1.  It by far is the easiest question, IMHO, solved by 92,000+ people. Next I’ll look into writing a class library with F#.

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• Programming Language, Turing Completeness and Turing Machine

  - by Amumu

  A programming language is said to be Turing Completeness if it can successfully simulate a universal TM. Let's take functional programming language for example. In functional programming, function has highest priority over anything. You can pass functions around like any primitives or objects. This is called first class function. In functional programming, your function does not produce side effect i.e. output strings onto screen, change the state of variables outside of its scope. Each function has a copy of its own objects if the objects are passed from the outside, and the copied objects are returned once the function finishes its job. Each function written purely in functional style is completely independent to anything outside of it. Thus, the complexity of the overall system is reduced. This is referred as referential transparency. In functional programming, each function can have its local variables kept its values even after the function exits. This is done by the garbage collector. The value can be reused the next time the function is called again. This is called memoization. A function usually should solve only one thing. It should model only one algorithm to answer a problem. Do you think that a function in a functional language with above properties simulate a Turing Machines? Functions (= algorithms = Turing Machines) are able to be passed around as input and returned as output. TM also accepts and simulate other TMs Memoization models the set of states of a Turing Machine. The memorized variables can be used to determine states of a TM (i.e. which lines to execute, what behavior should it take in a give state ...). Also, you can use memoization to simulate your internal tape storage. In language like C/C++, when a function exits, you lose all of its internal data (unless you store it elsewhere outside of its scope). The set of symbols are the set of all strings in a programming language, which is the higher level and human-readable version of machine code (opcode) Start state is the beginning of the function. However, with memoization, start state can be determined by memoization or if you want, switch/if-else statement in imperative programming language. But then, you can't Final accepting state when the function returns a value, or rejects if an exception happens. Thus, the function (= algorithm = TM) is decidable. Otherwise, it's undecidable. I'm not sure about this. What do you think? Is my thinking true on all of this? The reason I bring function in functional programming because I think it's closer to the idea of TM. What experience with other programming languages do you have which make you feel the idea of TM and the ideas of Computer Science in general? Can you specify how you think?

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• Customer Experience and BPM – From Efficiency to Engagement

  - by Ajay Khanna

  Over the last few years, focus of BPM has been mainly to improve the businesses efficiency. To create more efficient processes, to remove bottlenecks, to automate processes. That still holds true and why not? Isn’t BPM all about continuous improvement? BPM facilitates and requires business and IT collaboration. But business also requires working with customer. Do we not want to get close to and collaborate with our customers? This is where Social BPM takes BPM a step further. It not only allows people within an organization to collaborate to design exceptional processes, not only lets them collaborate on resolving a case but also let them engage with the customers. Engaging with customer means, first of all, connecting with them on their terms and turf. Take a new account opening process. Can a customer call you and initiate the process? Can a customer email you, or go to the website and initiate the process? Can they tweet you and initiate the process? Can they check the status of process via any channel they like? Can they take a picture of damaged package delivery and kick-off a returns process from their mobile device, with GIS data? Yes, these are various aspects to consider during process design if the goal is better customer experience and engagement. Of course, we want to be efficient and agile, but the focus here needs to be the customer. Now when the customer is tweeting about your products, posting on Facebook and Yelp about their experience with your company (and your process), you need to seek out that information. You need to gather and analyze the customer’s feedback on the social media and use that information to improve the processes and products. This is an excellent source of product and process ideation. So BPM is no longer only about improving back-office process efficiency, it is moving into a new and exciting phase of improving frontline customer facing processes, customer experience and engagement. Let me know how you think BPM can enhance customer experience.

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• Running C++ AMP kernels on the CPU

  - by Daniel Moth

  One of the FAQs we receive is whether C++ AMP can be used to target the CPU. For targeting multi-core we have a technology we released with VS2010 called PPL, which has had enhancements for VS 11 – that is what you should be using! FYI, it also has a Linux implementation via Intel's TBB which conforms to the same interface. When you choose to use C++ AMP, you choose to take advantage of massively parallel hardware, through accelerators like the GPU. Having said that, you can always use the accelerator class to check if you are running on a system where the is no hardware with a DirectX 11 driver, and decide what alternative code path you wish to follow.  In fact, if you do nothing in code, if the runtime does not find DX11 hardware to run your code on, it will choose the WARP accelerator which will run your code on the CPU, taking advantage of multi-core and SSE2 (depending on the CPU capabilities WARP also uses SSE3 and SSE 4.1 – it does not currently use AVX and on such systems you hopefully have a DX 11 GPU anyway). A few things to know about WARP It is our fallback CPU solution, not intended as a primary target of C++ AMP. WARP stands for Windows Advanced Rasterization Platform and you can read old info on this MSDN page on WARP. What is new in Windows 8 Developer Preview is that WARP now supports DirectCompute, which is what C++ AMP builds on. It is not currently clear if we will have a CPU fallback solution for non-Windows 8 platforms when we ship. When you create a WARP accelerator, its is_emulated property returns true. WARP does not currently support double precision.   BTW, when we refer to WARP, we refer to this accelerator described above. If we use lower case "warp", that refers to a bunch of threads that run concurrently in lock step and share the same instruction. In the VS 11 Developer Preview, the size of warp in our Ref emulator is 4 – Ref is another emulator that runs on the CPU, but it is extremely slow not intended for production, just for debugging. Comments about this post by Daniel Moth welcome at the original blog.

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• Check if an object is facing another based on angles

  - by Isaiah

  I already have something that calculates the bearing angle to get one object to face another. You give it the positions and it returns the angle to get one to face the other. Now I need to figure out how tell if on object is facing toward another object within a specified field and I can't find any information about how to do this. The objects are obj1 and obj2. Their angles are at obj1.angle and obj2.angle. Their vectors are at obj1.pos and obj2.pos. It's in the format [x,y]. The angle to have one face directly at another is found with direction(obj1.pos,obj2.pos). I want to set the function up like this: isfacing(obj1,obj2,area){...} and return true/false depending if it's in the specified field area to the angle to directly see it. I've got a base like this: var isfacing = function (obj1,obj2,area){ var toface = direction(obj1.pos,obj2.pos); if(toface+area >= obj1.angle && ob1.angle >= toface-area){ return true; } return false; } But my problem is that the angles are in 360 degrees, never above 360 and never below 0. How can I account for that in this? If the first object's angle is say at 0 and say I subtract a field area of 20 or so. It'll check if it's less than -20! If I fix the -20 it becomes 340 but x < 340 isn't what I want, I'd have to x 340 in that case. Is there someone out there with more sleep than I that can help a new dev pulling an all-nighter just to get enemies to know if they're attacking in the right direction? I hope I'm making this harder than it seems. I'd just make them always face the main char if the producer didn't want attacks from behind to work while blocking. In which case I'll need the function above anyways. I've tried to give as much info as I can think would help. Also this is in 2d.

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• OpenGLES GLSL Shader attributes always bound to 0

  - by codemonkey

  So I have a very simple vertex shader as follows #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; gl_Position = mvp * vec4(position, 1.0); } Which I load, as well as the fragment shader: #version 120 varying vec3 fragColor; void main(void) { gl_FragColor = vec4(fragColor,1.0); } Which I then load, compile, and link to my shader program. I check for link status using glGetProgramiv(shaderProgram, GL_LINK_STATUS, &shaderSuccess); which returns GL_TRUE so I think its ok. However, when I query the active attributes and uniforms using #ifdef DEBUG int totalAttributes = -1; glGetProgramiv(shaderProgram, GL_ACTIVE_ATTRIBUTES, &totalAttributes); for(int i=0; i<totalAttributes; ++i) { int name_len=-1, num=-1; GLenum type = GL_ZERO; char name[100]; glGetActiveAttrib(shaderProgram, GLuint(i), sizeof(name)-1, &name_len, &num, &type, name ); name[name_len] = 0; GLuint location = glGetAttribLocation(shaderProgram, name); fprintf(stderr, "Attribute %s is bound at %d\n", name, location); } int totalUniforms = -1; glGetProgramiv(shaderProgram, GL_ACTIVE_UNIFORMS, &totalUniforms); for(int i=0; i<totalUniforms; ++i) { int name_len=-1, num=-1; GLenum type = GL_ZERO; char name[100]; glGetActiveUniform(shaderProgram, GLuint(i), sizeof(name)-1, &name_len, &num, &type, name ); name[name_len] = 0; GLuint location = glGetUniformLocation(shaderProgram, name); fprintf(stderr, "Uniform %s is bound at %d\n", name, location); } #endif I get: Attribute inColor is bound at 0 Attribute position is bound at 1 Uniform mvp is bound at 0 Which leads to failure when trying to use the shader to render the objects. I have tried switching the order of declaration of position & inColor, but still, only position is bound with the other two giving 0 Can someone please explain why this is happening? Thanks

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• ConsumeStructuredBuffer, what am I doing wrong?

  - by John

  I'm trying to implement the 3rd exercise in chapter 12 of Introduction to 3D Game Programming with DirectX 11, that is: Implement a Compute Shader to calculate the length of 64 vectors. Previous exercises ask you to do the same with typed buffers and regular structured buffers and I had no problems with them. For what I've read, [Consume|Append]StructuredBuffers are bound to the pipeline using UnorderedAccessViews (as long as they use the D3D11_BUFFER_UAV_FLAG_APPEND, and the buffers have both D3D11_BIND_SHADER_RESOURCE and D3D11_BIND_UNORDERED_ACCESS bind flags). Problem is: my AppendStructuredBuffer works, since I can append data to it and retrieve it from the application to write to a results file, but the ConsumeStructuredBuffer always returns zeroed data. Data is in the buffer, since if I change the UAV to a ShaderResourceView and to a StructuredBuffer in the HLSL side it works. I don't know what I am missing: Should I initialize the ConsumeStructuredBuffer on the GPU, or can I do it when I create the buffer (as I amb currently doing). Is it OK to bind the buffer with a UAV as described above? Do I need to bind it as a ShaderResourceView somehow? Maybe I am missing some step? This is the declaration of buffers in the Compute Shader: struct Data { float3 v; }; struct Result { float l; }; ConsumeStructuredBuffer<Data> gInput; AppendStructuredBuffer<Result> gOutput; And here the creation of the buffer and UAV for input data: D3D11_BUFFER_DESC inputDesc; inputDesc.Usage = D3D11_USAGE_DEFAULT; inputDesc.ByteWidth = sizeof(Data) * mNumElements; inputDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_UNORDERED_ACCESS; inputDesc.CPUAccessFlags = 0; inputDesc.StructureByteStride = sizeof(Data); inputDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED; D3D11_SUBRESOURCE_DATA vinitData; vinitData.pSysMem = &data[0]; HR(md3dDevice->CreateBuffer(&inputDesc, &vinitData, &mInputBuffer)); D3D11_UNORDERED_ACCESS_VIEW_DESC uavDesc; uavDesc.Format = DXGI_FORMAT_UNKNOWN; uavDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER; uavDesc.Buffer.FirstElement = 0; uavDesc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_APPEND; uavDesc.Buffer.NumElements = mNumElements; md3dDevice->CreateUnorderedAccessView(mInputBuffer, &uavDesc, &mInputUAV); Initial data is an array of Data structs, which contain a XMFLOAT3 with random data. I bind the UAV to the shader using the Effects framework: ID3DX11EffectUnorderedAccessViewVariable* Input = mFX->GetVariableByName("gInput")->AsUnorderedAccessView(); Input->SetUnorderedAccessView(uav); // uav is mInputUAV Any ideas? Thank you.

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• As a tooling/automation developer, can I be making better use of OOP?

  - by Tom Pickles

  My time as a developer (~8 yrs) has been spent creating tooling/automation of one sort or another. The tools I develop usually interface with one or more API's. These API's could be win32, WMI, VMWare, a help-desk application, LDAP, you get the picture. The apps I develop could be just to pull back data and store/report. It could be to provision groups of VM's to create live like mock environments, update a trouble ticket etc. I've been developing in .Net and I'm currently reading into design patterns and trying to think about how I can improve my skills to make better use of and increase my understanding of OOP. For example, I've never used an interface of my own making in anger (which is probably not a good thing), because I honestly cannot identify where using one would benefit later on when modifying my code. My classes are usually very specific and I don't create similar classes with similar properties/methods which could use a common interface (like perhaps a car dealership or shop application might). I generally use an n-tier approach to my apps, having a presentation layer, a business logic/manager layer which interfaces with layer(s) that make calls to the API's I'm working with. My business entities are always just method-less container objects, which I populate with data and pass back and forth between my API interfacing layer using static methods to proxy/validate between the front and the back end. My code by nature of my work, has few common components, at least from what I can see. So I'm struggling to see how I can better make use of OOP design and perhaps reusable patterns. Am I right to be concerned that I could be being smarter about how I work, or is what I'm doing now right for my line of work? Or, am I missing something fundamental in OOP? EDIT: Here is some basic code to show how my mgr and api facing layers work. I use static classes as they do not persist any data, only facilitate moving it between layers. public static class MgrClass { public static bool PowerOnVM(string VMName) { // Perform logic to validate or apply biz logic // call APIClass to do the work return APIClass.PowerOnVM(VMName); } } public static class APIClass { public static bool PowerOnVM(string VMName) { // Calls to 3rd party API to power on a virtual machine // returns true or false if was successful for example } }

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• Deferred Shading - Toolkit

  - by AliveDevil

  I recently managed to get some lights rendered in a scene by using a buffer and a for-loop. The problem with this method is the performance drop if more lights are used. I tried to convert Deferred Rendering in XNA4.0 | ROY-T.NL but it is not working, because I am not using any models. I know I have to render color, normals and lights seperate but I don't know how I could get it working. For understanding my structure better I'm using a world-class which holds some chunks. These chunks are loading all vertices from their items. These items have a property which returns the vertices. The item is returning VertexPositionNormalTexture[]. The chunk loads these Vertices and combines them to one large array of VertexPositionNormalTexture via someList.AsParallel().SelectMany(m => m).ToArray()). m is a VertexPositionNormalTexture. someList is List<VertexPositionNormalTexture>. I got my own shader to draw these vertices how I want them to be drawn. The first thing I would try is setting up two RenderTarget2D for rendering the color and normal part. With two different shaders. Than I would have to render the lights and there's the problem: I don't know how. I set up a structure to simplify working with lights but it didn't really help. public struct Light { public Vector3 Position; public Color4 Color; public float Range; public float Intensity; public Light( Vector3 position, Color color, float range, float intensity ) : this() { this.Position = position; this.Color = color; this.Range = range; this.Intensity = intensity; } public float[] Definition { get { return new[] { Position.X, Position.Y, Position.Z, Color.Red, Color.Green, Color.Blue, Intensity, Range }; } } } The next part is equally different because I don't know how to combine the colorMap, normalMap and textureMap to one finalMap. Some information to the system: I'm using SharpDX (Nightly from some months ago) and the SharpDX.Toolkit (I don't want to mess up with Direct3DDevice and similar things). Can someone help me with this problem? If things are missing or I provided insufficient information tell me, I need to get deferred shading working. Things I'm not able to do: create a rendertarget which holds all lights, merge colorMap, normalMap and lightMap to one finalMap and presenting this to the user.

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• Question about BoundingSpheres and Ray intersections

  - by NDraskovic

  I'm working on a XNA project (not really a game) and I'm having some trouble with picking algorithm. I have a few types of 3D models that I draw to the screen, and one of them is a switch. So I'm trying to make a picking algorithm that would enable the user to click on the switch and that would trigger some other function. The problem is that the BoundingSphere.Intersect() method always returns null as result. This is the code I'm using: In the declaration section: ` //Basic matrices private Matrix world = Matrix.CreateTranslation(new Vector3(0, 0, 0)); private Matrix view = Matrix.CreateLookAt(new Vector3(10, 10, 10), new Vector3(0, 0, 0), Vector3.UnitY); private Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45), 800f / 600f, 0.01f, 100f); //Collision detection variables Viewport mainViewport; List<BoundingSphere> spheres = new List<BoundingSphere>(); Ray ControlRay; Vector3 nearPoint, farPoint, nearPlane, farPlane, direction; ` And then in the Update method: ` nearPlane = new Vector3((float)Mouse.GetState().X, (float)Mouse.GetState().Y, 0.0f); farPlane = new Vector3((float)Mouse.GetState().X, (float)Mouse.GetState().Y, 10.0f); nearPoint = GraphicsDevice.Viewport.Unproject(nearPlane, projection, view, world); farPoint = GraphicsDevice.Viewport.Unproject(farPlane, projection, view, world); direction = farPoint - nearPoint; direction.Normalize(); ControlRay = new Ray(nearPoint, direction); if (spheres.Count != 0) { for (int i = 0; i < spheres.Count; i++) { if (spheres[i].Intersects(ControlRay) != null) { Window.Title = spheres[i].Center.ToString(); } else { Window.Title = "Empty"; } } ` The "spheres" list gets filled when the 3D object data gets loaded (I read it from a .txt file). For every object marked as switch (I use simple numbers to determine which object is to be drawn), a BoundingSphere is created (center is on the coordinates of the 3D object, and the diameter is always the same), and added to the list. The objects are drawn normally (and spheres.Count is not 0), I can see them on the screen, but the Window title always says "Empty" (of course this is just for testing purposes, I will add the real function when I get positive results) meaning that there is no intersection between the ControlRay and any of the bounding spheres. I think that my basic matrices (world, view and projection) are making some problems, but I cant figure out what. Please help.

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• Why can't a blendShader sample anything but the current coordinate of the background image?

  - by Triynko

  In Flash, you can set a DisplayObject's blendShader property to a pixel shader (flash.shaders.Shader class). The mechanism is nice, because Flash automatically provides your Shader with two input images, including the background surface and the foreground display object's bitmap. The problem is that at runtime, the shader doesn't allow you to sample the background anywhere but under the current output coordinate. If you try to sample other coordinates, it just returns the color of the current coordinate instead, ignoring the coordinates you specified. This seems to occur only at runtime, because it works properly in the Pixel Bender toolkit. This limitation makes it impossible to simulate, for example, the Aero Glass effect in Windows Vista/7, because you cannot sample the background properly for blurring. I must mention that it is possible to create the effect in Flash through manual composition techniques, but it's hard to determine when it actually needs updated, because Flash does not provide information about when a particular area of the screen or a particular display object needs re-rendered. For example, you may have a fixed glass surface with objects moving underneath it that don't dispatch events when they move. The only alternative is to re-render the glass bar every frame, which is inefficient, which is why I am trying to do it through a blendShader so Flash determines when it needs rendered automatically. Is there a technical reason for this limitation, or is it an oversight of some sort? Does anyone know of a workaround, or a way I could provide my manual composition implementation with information about when it needs re-rendered? The limitation is mentioned with no explanation in the last note in this page: http://help.adobe.com/en_US/as3/dev/WSB19E965E-CCD2-4174-8077-8E5D0141A4A8.html It says: "Note: When a Pixel Bender shader program is run as a blend in Flash Player or AIR, the sampling and outCoord() functions behave differently than in other contexts.In a blend, a sampling function will always return the current pixel being evaluated by the shader. You cannot, for example, use add an offset to outCoord() in order to sample a neighboring pixel. Likewise, if you use the outCoord() function outside a sampling function, its coordinates always evaluate to 0. You cannot, for example, use the position of a pixel to influence how the blended images are combined."

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• Is 2 lines of push/pop code for each pre-draw-state too many?

  - by Griffin

  I'm trying to simplify vector graphics management in XNA; currently by incorporating state preservation. 2X lines of push/pop code for X states feels like too many, and it just feels wrong to have 2 lines of code that look identical except for one being push() and the other being pop(). The goal is to eradicate this repetitiveness,and I hoped to do so by creating an interface in which a client can give class/struct refs in which he wants restored after the rendering calls. Also note that many beginner-programmers will be using this, so forcing lambda expressions or other advanced C# features to be used in client code is not a good idea. I attempted to accomplish my goal by using Daniel Earwicker's Ptr class: public class Ptr<T> { Func<T> getter; Action<T> setter; public Ptr(Func<T> g, Action<T> s) { getter = g; setter = s; } public T Deref { get { return getter(); } set { setter(value); } } } an extension method: //doesn't work for structs since this is just syntatic sugar public static Ptr<T> GetPtr <T> (this T obj) { return new Ptr<T>( ()=> obj, v=> obj=v ); } and a Push Function: //returns a Pop Action for later calling public static Action Push <T> (ref T structure) where T: struct { T pushedValue = structure; //copies the struct data Ptr<T> p = structure.GetPtr(); return new Action( ()=> {p.Deref = pushedValue;} ); } However this doesn't work as stated in the code. How might I accomplish my goal? Example of code to be refactored: protected override void RenderLocally (GraphicsDevice device) { if (!(bool)isCompiled) {Compile();} //TODO: make sure state settings don't implicitly delete any buffers/resources RasterizerState oldRasterState = device.RasterizerState; DepthFormat oldFormat = device.PresentationParameters.DepthStencilFormat; DepthStencilState oldBufferState = device.DepthStencilState; { //Rendering code } device.RasterizerState = oldRasterState; device.DepthStencilState = oldBufferState; device.PresentationParameters.DepthStencilFormat = oldFormat; }

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• Data Transformation Pipeline

  - by davenewza

  I have create some kind of data pipeline to transform coordinate data into more useful information. Here is the shell of pipeline: public class PositionPipeline { protected List<IPipelineComponent> components; public PositionPipeline() { components = new List<IPipelineComponent>(); } public PositionPipelineEntity Process(Position position) { foreach (var component in components) { position = component.Execute(position); } return position; } public PositionPipeline RegisterComponent(IPipelineComponent component) { components.Add(component); return this; } } Every IPipelineComponent accepts and returns the same type - a PositionPipelineEntity. Code: public interface IPipelineComponent { PositionPipelineEntity Execute(PositionPipelineEntity position); } The PositionPipelineEntity needs to have many properties, many which are unused in certain components and required in others. Some properties will also have become redundant at the end of the pipeline. For example, these components could be executed: TransformCoordinatesComponent: Parse the raw coordinate data into a Coordinate type. DetermineCountryComponent: Determine and stores country code. DetermineOnRoadComponent: Determine and store whether coordinate is on a road. Code: pipeline .RegisterComponent(new TransformCoordinatesComponent()) .RegisterComponent(new DetermineCountryComponent()) .RegisterComponent(new DetermineOnRoadComponent()); pipeline.Process(positionPipelineEntity); The PositionPipelineEntity type: public class PositionPipelineEntity { // Only relevant to the TransformCoordinatesComponent public decimal RawCoordinateLatitude { get; set; } // Only relevant to the TransformCoordinatesComponent public decimal RawCoordinateLongitude { get; set; } // Required by all components after TransformCoordinatesComponent public Coordinate CoordinateLatitude { get; set; } // Required by all components after TransformCoordinatesComponent public Coordinate CoordinateLongitude { get; set; } // Set in DetermineCountryComponent, not required anywhere. // Requires CoordinateLatitude and CoordinateLongitude (TransformCoordinatesComponent) public string CountryCode { get; set; } // Set in DetermineOnRoadComponent, not required anywhere. // Requires CoordinateLatitude and CoordinateLongitude (TransformCoordinatesComponent) public bool OnRoad { get; set; } } Problems: I'm very concerned about the dependency that a component has on properties. The way to solve this would be to create specific types for each component. The problem then is that I cannot chain them together like this. The other problem is the order of components in the pipeline matters. There is some dependency. The current structure does not provide any static or runtime checking for such a thing. Any feedback would be appreciated.

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• Incorrect results for frustum cull

  - by DeadMG

  Previously, I had a problem with my frustum culling producing too optimistic results- that is, including many objects that were not in the view volume. Now I have refactored that code and produced a cull that should be accurate to the actual frustum, instead of an axis-aligned box approximation. The problem is that now it never returns anything to be in the view volume. As the mathematical support library I'm using does not provide plane support functions, I had to code much of this functionality myself, and I'm not really the mathematical type, so it's likely that I've made some silly error somewhere. As follows is the relevant code: class Plane { public: Plane() { r0 = Math::Vector(0,0,0); normal = Math::Vector(0,1,0); } Plane(Math::Vector p1, Math::Vector p2, Math::Vector p3) { r0 = p1; normal = Math::Cross((p2 - p1), (p3 - p1)); } Math::Vector r0; Math::Vector normal; }; This class represents one plane as a point and a normal vector. class Frustum { public: Frustum( const std::array<Math::Vector, 8>& points ) { planes[0] = Plane(points[0], points[1], points[2]); planes[1] = Plane(points[4], points[5], points[6]); planes[2] = Plane(points[0], points[1], points[4]); planes[3] = Plane(points[2], points[3], points[6]); planes[4] = Plane(points[0], points[2], points[4]); planes[5] = Plane(points[1], points[3], points[5]); } Plane planes[6]; }; The points are passed in order where (the inverse of) each bit of the index of each point indicates whether it's the left, top, and back of the frustum, respectively. As such, I just picked any three points where they all shared one bit in common to define the planes. My intersection test is as follows (based on this): bool Intersects(Math::AABB lhs, const Frustum& rhs) const { for(int i = 0; i < 6; i++) { Math::Vector pvertex = lhs.TopRightFurthest; Math::Vector nvertex = lhs.BottomLeftClosest; if (rhs.planes[i].normal.x <= -0.0f) { std::swap(pvertex.x, nvertex.x); } if (rhs.planes[i].normal.y <= -0.0f) { std::swap(pvertex.y, nvertex.y); } if (rhs.planes[i].normal.z <= -0.0f) { std::swap(pvertex.z, nvertex.z); } if (Math::Dot(rhs.planes[i].r0, nvertex) < 0.0f) { return false; } } return true; } Also of note is that because I'm using a left-handed co-ordinate system, I wrote my Cross function to return the negative of the formula given on Wikipedia. Any suggestions as to where I've made a mistake?

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• Is code like this a "train wreck" (in violation of Law of Demeter)?

  - by Michael Kjörling

  Browsing through some code I've written, I came across the following construct which got me thinking. At a first glance, it seems clean enough. Yes, in the actual code the getLocation() method has a slightly more specific name which better describes exactly which location it gets. service.setLocation(this.configuration.getLocation().toString()); In this case, service is an instance variable of a known type, declared within the method. this.configuration comes from being passed in to the class constructor, and is an instance of a class implementing a specific interface (which mandates a public getLocation() method). Hence, the return type of the expression this.configuration.getLocation() is known; specifically in this case, it is a java.net.URL, whereas service.setLocation() wants a String. Since the two types String and URL are not directly compatible, some sort of conversion is required to fit the square peg in the round hole. However, according to the Law of Demeter as cited in Clean Code, a method f in class C should only call methods on C, objects created by or passed as arguments to f, and objects held in instance variables of C. Anything beyond that (the final toString() in my particular case above, unless you consider a temporary object created as a result of the method invocation itself, in which case the whole Law seems to be moot) is disallowed. Is there a valid reasoning why a call like the above, given the constraints listed, should be discouraged or even disallowed? Or am I just being overly nitpicky? If I were to implement a method URLToString() which simply calls toString() on a URL object (such as that returned by getLocation()) passed to it as a parameter, and returns the result, I could wrap the getLocation() call in it to achieve exactly the same result; effectively, I would just move the conversion one step outward. Would that somehow make it acceptable? (It seems to me, intuitively, that it should not make any difference either way, since all that does is move things around a little. However, going by the letter of the Law of Demeter as cited, it would be acceptable, since I would then be operating directly on a parameter to a function.) Would it make any difference if this was about something slightly more exotic than calling toString() on a standard type? When answering, do keep in mind that altering the behavior or API of the type that the service variable is of is not practical. Also, for the sake of argument, let's say that altering the return type of getLocation() is also impractical.

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• No wireless connection using a conceptronic c54i (RT2561/RT61 rev B)

  - by jrosell

  Detected but not working. New install on ubuntu 11.10 using coneptronic C54Ri. As documentation says it uses Ralink drivers.... Any ideas why my wireless does not work? $ lspci -nn | grep -i 'ralink' 01:05.0 Network controller: Ralink corp. RT2561/RT61 rev B 802.11g ifconfig eth0 Link encap:Ethernet HWaddr 00:1e:90:e5:af:13 inet addr:192.168.0.197 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::21e:90ff:fee5:af13/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:28361 errors:0 dropped:0 overruns:0 frame:0 TX packets:16858 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:39812172 (39.8 MB) TX bytes:1633405 (1.6 MB) Interrupt:43 Base address:0xc000 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:16436 Metric:1 RX packets:80 errors:0 dropped:0 overruns:0 frame:0 TX packets:80 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:6608 (6.6 KB) TX bytes:6608 (6.6 KB) iwconfig wlan0 wlan0 IEEE 802.11abg ESSIDff/any Mode:Managed Access Point: Not-Associated Tx-Power=0 dBm Retry long limit:7 RTS thrff Fragment thrff Power Managementff lsmod | grep rt rt61pci 27493 0 crc_itu_t 12627 1 rt61pci rt2x00pci 14202 1 rt61pci rt2x00lib 48114 2 rt61pci,rt2x00pci mac80211 272785 2 rt2x00pci,rt2x00lib cfg80211 172392 2 rt2x00lib,mac80211 eeprom_93cx6 12653 1 rt61pci parport_pc 32114 1 parport 40930 3 ppdev,parport_pc,lp lsmod | grep rt [ 2497.816989] phy0 -> rt2x00pci_regbusy_read: Error - Indirect register access failed: offset=0x0000308c, value=0xffffffff [ 2497.827112] phy0 -> rt2x00pci_regbusy_read: Error - Indirect register access failed: offset=0x0000308c, value=0xffffffff [ 2497.837430] phy0 -> rt2x00pci_regbusy_read: Error - Indirect register access failed: offset=0x0000308c, value=0xffffffff [ 2497.847528] phy0 -> rt2x00pci_regbusy_read: Error - Indirect register access failed: offset=0x0000308c, value=0xffffffff [ 2497.847632] phy0 -> rt61pci_wait_bbp_ready: Error - BBP register access faile d, aborting. [ 2497.847637] phy0 -> rt61pci_set_device_state: Error - Device failed to enter state 4 (-5). sudo lshw -C network *-network DISABLED description: Wireless interface product: RT2561/RT61 rev B 802.11g vendor: Ralink corp. physical id: 5 bus info: pci@0000:01:05.0 logical name: wlan0 version: 00 serial: fa:b8:14:58:62:35 width: 32 bits clock: 33MHz capabilities: pm cap_list ethernet physical wireless configuration: broadcast=yes driver=rt61pci driverversion=3.0.0-12-generic firmware=0.8 latency=0 link=no multicast=yes wireless=IEEE 802.11abg resources: irq:16 memory:fdef8000-fdefffff iwlist scan lo Interface doesn't support scanning. eth0 Interface doesn't support scanning. wlan0 Failed to read scan data : Network is down uname -mr 3.0.0-12-generic i686 Edit 1 $ rfkill list all 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no On reboot, sudo lshw -C network returns network is ok. Hovever, WPA keeps on asking the wireless key

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• C# 5: At last, async without the pain

  - by Alex.Davies

  For me, the best feature in Visual Studio 11 is the async and await keywords that come with C# 5. I am a big fan of asynchronous programming: it frees up resources, in particular the thread that a piece of code needs to run in. That lets that thread run something else, while waiting for your long-running operation to complete. That's really important if that thread is the UI thread, or if it's holding a lock because it accesses some data structure. Before C# 5, I think I was about the only person in the world who really cared about asynchronous programming. The trouble was that you had to go to extreme lengths to make code asynchronous. I would forever be writing methods that, instead of returning a value, accepted an extra argument that is a "continuation". Then, when calling the method, I'd have to pass a lambda in to it, which contained all the stuff that needed to happen after the method finished. Here is a real snippet of code that is in .NET Demon: m_BuildControl.FilterEnabledForBuilding(     projects,     enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(         enabledProjects,         newDirtyProjects =         {             // Mark any currently broken projects as dirty             newDirtyProjects.UnionWith(m_BrokenProjects);             // Copy what we found into the set of dirty things             m_DirtyProjects = newDirtyProjects;             RunSomeBuilds();         })); It's just obtuse. Who puts a lambda inside a lambda like that? Well, me obviously. But surely enabledProjects should just be the return value of FilterEnabledForBuilding? And newDirtyProjects should just be the return value of FilterNeedsBuilding? C# 5 async/await lets you write asynchronous code without it looking so stupid. Here's what I plan to change that code to, once we upgrade to VS 11: var enabledProjects = await m_BuildControl.FilterEnabledForBuilding(projects); var newDirtyProjects = await m_OutOfDateProjectFinder.FilterNeedsBuilding(enabledProjects); // Mark any currently broken projects as dirty newDirtyProjects.UnionWith(m_BrokenProjects); // Copy what we found into the set of dirty things m_DirtyProjects = newDirtyProjects; RunSomeBuilds(); Much easier to read! But how is this the same code? If we were on the UI thread, doesn't the UI thread have to block while FilterEnabledForBuilding runs? No, it doesn't, and that's the magic of the await keyword! It cuts your method up into its constituent pieces, much like I did manually with lambdas before. When you run it, only the piece up to the first await actually runs. The rest is passed to FilterEnabledForBuilding as a continuation, which will get called back whenever that method is finished. In the meantime, our thread returns, and can go back to making the UI responsive, or whatever else threads do in their spare time. This is actually a massive simplification, and if you're interested in all the gory details, and speed hacks that the await keyword actually does for you, I recommend Jon Skeet's blog posts about it.

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• Unable to ping inside or outside network with default gateway 0.0.0.0

  - by agentroadkill

  I've been around here before and I could usually piece together everything to more or less get myself up and running, but this time I'm truly stumped. I'm trying to connect my new 14.04 install to a network, and I'm forced to be behind my college's router. Now I've tested the vary cable that is right now plugged into my Ubuntu box on a Windows, Mac OS X, and even my friend's Ubuntu 14.04 box, and they all connect no problem. I've been trying to track this down for about two days, but every time I get close to it, the bug jumps to some other piece of my connection. Anyway, as it sits ifconfig -a gives: eth2 Lninkencap:Ethernet HWaddr:00:1f:bc:08:31:1d inet addr:10.32.51.51 Bcast:10.32.51.155 Mask: 255.255.255.0 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 RX bytes:0 TX bytes:0 as well as the local loopback, but I'm assuming that is not an issue here. sudo dhclient -v eth2 returns: Listening on LPF/<hardware address of my integrated NIC, above> Sending on <same> Sending on Socket/fallback DHCPREQUEST of 10.32.51.51 on eth2 to 255.255.255.255 port 67 (xid=0x6f4a66ba) <two more lines of same> DHCPDISCOVER on eth2 to 255.255.255.255 port 67 interval 3 (xid=0x156f9fb4) <many more of above with varying intervals> No DHCPOFFERS received. Trying recorded lease 10.32.51.51 RTNETLINK answers: File exists bound: renewal in <large number> seconds If I then try ping 8.8.8.8, I get: connect: Network is unreachable /etc/resolv.conf only contains the two lines telling you not to edit it, while /etc/network/interfaces only has the loopback interface block in it. I've tried commenting out the "option rfc3442" line in /etc/dhcp/dhclient.conf which seemed to fix this issue for many people, as well as adding the line send vendor-class-indentifier "MSFT5.0" to dhclient.conf as well to tell the router I'm a windows box, in case they don't like Linux. Finally, route -n reveals: Destination Gateway Genmask Flags Metric Ref Use Iface 10.32.51.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2 I would like to apologize in advance for the doubtless butchered text alignment, but I'm obviously typing this all by hand, reading from the terminal as I type commands. I'm hoping this is an interesting problem, and not something I blithely stumbled past in my (apparent) over-confidence. TIA! Quick addendum before posting: The activity light on the ethernet port are lit and one blinks during boot, but they rarely (and seemingly randomly) do so afterwards (both are dark) even while running dhclient in the foreground. When I had the Ubuntu box tethered to my MacBook earlier, I got what looked like a normal power/uplink blinking pattern, but was unable to ping one from the other.

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