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  • Creating a Corporate Data Hub

    - by BuckWoody
    The Windows Azure Marketplace has a rich assortment of data and software offerings for you to use – a type of Software as a Service (SaaS) for IT workers, not necessarily for end-users. Among those offerings is the “Data Hub” – a  codename for a project that ironically actually does what the codename says. In many of our organizations, we have multiple data quality issues. Finding data is one problem, but finding it just once is often a bigger problem. Lots of departments and even individuals have stored the same data more than once, and in some cases, made changes to one of the copies. It’s difficult to know which location or version of the data is authoritative. Then there’s the problem of accessing the data. It’s fairly straightforward to publish a database, share or other location internally to store the data. But then you have to figure out who owns it, how it is controlled, and pass out the various connection strings to those who want to use it. And then you need to figure out how to let folks access the internal data externally – bringing up all kinds of security issues. Finally, in many cases our user community wants us to combine data from the internally sources with external data, bringing up the security, strings, and exploration features up all over again. Enter the Data Hub. This is an online offering, where you assign an administrator and data stewards. You import the data into the service, and it’s available to you - and only you and your organization if you wish. The basic steps for this service are to set up the portal for your company, assign administrators and permissions, and then you assign data areas and import data into them. From there you make them discoverable, and then you have multiple options that you or your users can access that data. You’re then able, if you wish, to combine that data with other data in one location. So how does all that work? What about security? Is it really that easy? And can you really move the data definition off to the Subject Matter Experts (SME’s) that know the particular data stack better than the IT team does? Well, nothing good is easy – but using the Data Hub is actually pretty simple. I’ll give you a link in a moment where you can sign up and try this yourself. Once you sign up, you assign an administrator. From there you’ll create data areas, and then use a simple interface to bring the data in. All of this is done in a portal interface – nothing to install, configure, update or manage. After the data is entered in, and you’ve assigned meta-data to describe it, your users have multiple options to access it. They can simply use the portal – which actually has powerful visualizations you can use on any platform, even mobile phones or tablets.     Your users can also hit the data with Excel – which gives them ultimate flexibility for display, all while using an authoritative, single reference for the data. Since the service is online, they can do this wherever they are – given the proper authentication and permissions. You can also hit the service with simple API calls, like this one from C#: http://msdn.microsoft.com/en-us/library/hh921924  You can make HTTP calls instead of code, and the data can even be exposed as an OData Feed. As you can see, there are a lot of options. You can check out the offering here: http://www.microsoft.com/en-us/sqlazurelabs/labs/data-hub.aspx and you can read the documentation here: http://msdn.microsoft.com/en-us/library/hh921938

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  • Some PowerShell goodness

    - by KyleBurns
    Ever work somewhere where processes dump files into folders to maintain an archive?  Me too and Windows Explorer hates it.  Very often I find myself needing to organize these files into subfolders so that I can go after files without locking up Windows Explorer and my answer used to be to write a program in something like C# to do the job.  These programs will typically enumerate the files in a folder and move each file to a subdirectory named based on a datestamp.  The last such program I wrote had to use lower-level Win32 API calls to perform the enumeration because it appears the standard .Net calls make use of the same method of enumerating the directories that Windows Explorer chokes on when dealing with a large number of entries in a particular directory, so a simple task was accomplished with a lot of code. Of course, this little utility was just something I used to make my life easier and "not a production app", so it was in my local source folder and not source control when my hard drive died.  So... I was getting ready to re-create it and thought it might be a good idea to play with PowerShell a bit - something I had been wanting to do but had not yet met a requirement to make me do it.  The resulting script was amazingly succinct and even building the flexibility for parameterization and adding line breaks for readability was only about 25 lines long.  Here's the code with discussion following: param(     [Parameter(         Mandatory = $false,         Position = 0,         HelpMessage = "Root of the folders or share to archive.  Be sure to end with appropriate path separator"     )]     [String] $folderRoot="\\fileServer\pathToFolderWithLotsOfFiles\",       [Parameter(         Mandatory = $false,         Position = 1     )]     [int] $days = 1 ) dir $folderRoot|?{(!($_.PsIsContainer)) -and ((get-date) - $_.lastwritetime).totaldays -gt $days }|%{     [string]$year=$([string]$_.lastwritetime.year)     [string]$month=$_.lastwritetime.month     [string]$day=$_.lastwritetime.day     $dir=$folderRoot+$year+"\"+$month+"\"+$day     if(!(test-path $dir)){         new-item -type container $dir     }     Write-output $_     move-item $_.fullname $dir } The script starts by declaring two parameters.  The first parameter holds the path to the folder that I am going to be sorting into subdirectories.  The path separator is intended to be included in this argument because I didn't want to mess with determining whether this was local or UNC and picking the right separator in code, but this could be easily improved upon using Path.Combine since PowerShell has access to the full framework libraries.  The second parameter holds a minimum age in days for files to be removed from the root folder.  The script then pipes the dir command through a query to include only files (by excluding containers) and of those, only entries that meet the age requirement based on the last modified datestamp.  For each of those, the datestamp is used to construct a folder name in the format YYYY\MM\DD (if you're in an environment where even a day's worth of files need further divided, you could make this more granular) and the folder is created if it does not yet exist.  Finally, the file is moved into the directory. One of the things that was really cool about using PowerShell for this task is that the new-item command is smart enough to create the entire subdirectory structure with a single call.  In previous code that I have written to do this kind of thing, I would have to test the entire tree leading down to the subfolder I want, leading to a lot of branching code that detracted from being able to quickly look at the code and understand the job it performs. Overall, I have to say I'm really pleased with what has been done making PowerShell powerful and useful.

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  • Bounding Box Collision Glitching Problem (Pygame)

    - by Ericson Willians
    So far the "Bounding Box" method is the only one that I know. It's efficient enough to deal with simple games. Nevertheless, the game I'm developing is not that simple anymore and for that reason, I've made a simplified example of the problem. (It's worth noticing that I don't have rotating sprites on my game or anything like that. After showing the code, I'll explain better). Here's the whole code: from pygame import * DONE = False screen = display.set_mode((1024,768)) class Thing(): def __init__(self,x,y,w,h,s,c): self.x = x self.y = y self.w = w self.h = h self.s = s self.sur = Surface((64,48)) draw.rect(self.sur,c,(self.x,self.y,w,h),1) self.sur.fill(c) def draw(self): screen.blit(self.sur,(self.x,self.y)) def move(self,x): if key.get_pressed()[K_w] or key.get_pressed()[K_UP]: if x == 1: self.y -= self.s else: self.y += self.s if key.get_pressed()[K_s] or key.get_pressed()[K_DOWN]: if x == 1: self.y += self.s else: self.y -= self.s if key.get_pressed()[K_a] or key.get_pressed()[K_LEFT]: if x == 1: self.x -= self.s else: self.x += self.s if key.get_pressed()[K_d] or key.get_pressed()[K_RIGHT]: if x == 1: self.x += self.s else: self.x -= self.s def warp(self): if self.y < -48: self.y = 768 if self.y > 768 + 48: self.y = 0 if self.x < -64: self.x = 1024 + 64 if self.x > 1024 + 64: self.x = -64 r1 = Thing(0,0,64,48,1,(0,255,0)) r2 = Thing(6*64,6*48,64,48,1,(255,0,0)) while not DONE: screen.fill((0,0,0)) r2.draw() r1.draw() # If not intersecting, then moves, else, it moves in the opposite direction. if not ((((r1.x + r1.w) > (r2.x - r1.s)) and (r1.x < ((r2.x + r2.w) + r1.s))) and (((r1.y + r1.h) > (r2.y - r1.s)) and (r1.y < ((r2.y + r2.h) + r1.s)))): r1.move(1) else: r1.move(0) r1.warp() if key.get_pressed()[K_ESCAPE]: DONE = True for ev in event.get(): if ev.type == QUIT: DONE = True display.update() quit() The problem: In my actual game, the grid is fixed and each tile has 64 by 48 pixels. I know how to deal with collision perfectly if I moved by that size. Nevertheless, obviously, the player moves really fast. In the example, the collision is detected pretty well (Just as I see in many examples throughout the internet). The problem is that if I put the player to move WHEN IS NOT intersecting, then, when it touches the obstacle, it does not move anymore. Giving that problem, I began switching the directions, but then, when it touches and I press the opposite key, it "glitches through". My actual game has many walls, and the player will touch them many times, and I can't afford letting the player go through them. The code-problem illustrated: When the player goes towards the wall (Fine). When the player goes towards the wall and press the opposite direction. (It glitches through). Here is the logic I've designed before implementing it: I don't know any other method, and I really just want to have walls fixed in a grid, but move by 1 or 2 or 3 pixels (Slowly) and have perfect collision without glitching-possibilities. What do you suggest?

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  • Dependency Injection Introduction

    - by MarkPearl
    I recently was going over a great book called “Dependency Injection in .Net” by Mark Seeman. So far I have really enjoyed the book and would recommend anyone looking to get into DI to give it a read. Today I thought I would blog about the first example Mark gives in his book to illustrate some of the benefits that DI provides. The ones he lists are Late binding Extensibility Parallel Development Maintainability Testability To illustrate some of these benefits he gives a HelloWorld example using DI that illustrates some of the basic principles. It goes something like this… class Program { static void Main(string[] args) { var writer = new ConsoleMessageWriter(); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } } public interface IMessageWriter { void Write(string message); } public class ConsoleMessageWriter : IMessageWriter { public void Write(string message) { Console.WriteLine(message); } } public class Salutation { private readonly IMessageWriter _writer; public Salutation(IMessageWriter writer) { _writer = writer; } public void Exclaim() { _writer.Write("Hello World"); } }   If you had asked me a few years ago if I had thought this was a good approach to solving the HelloWorld problem I would have resounded “No”. How could the above be better than the following…. class Program { static void Main(string[] args) { Console.WriteLine("Hello World"); Console.ReadLine(); } }  Today, my mind-set has changed because of the pain of past programs. So often we can look at a small snippet of code and make judgements when we need to keep in mind that we will most probably be implementing these patterns in projects with hundreds of thousands of lines of code and in projects that we have tests that we don’t want to break and that’s where the first solution outshines the latter. Let’s see if the first example achieves some of the outcomes that were listed as benefits of DI. Could I test the first solution easily? Yes… We could write something like the following using NUnit and RhinoMocks… [TestFixture] public class SalutationTests { [Test] public void ExclaimWillWriteCorrectMessageToMessageWriter() { var writerMock = MockRepository.GenerateMock<IMessageWriter>(); var sut = new Salutation(writerMock); sut.Exclaim(); writerMock.AssertWasCalled(x => x.Write("Hello World")); } }   This would test the existing code fine. Let’s say we then wanted to extend the original solution so that we had a secure message writer. We could write a class like the following… public class SecureMessageWriter : IMessageWriter { private readonly IMessageWriter _writer; private readonly string _secretPassword; public SecureMessageWriter(IMessageWriter writer, string secretPassword) { _writer = writer; _secretPassword = secretPassword; } public void Write(string message) { if (_secretPassword == "Mark") { _writer.Write(message); } else { _writer.Write("Unauthenticated"); } } }   And then extend our implementation of the program as follows… class Program { static void Main(string[] args) { var writer = new SecureMessageWriter(new ConsoleMessageWriter(), "Mark"); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } }   Our application has now been successfully extended and yet we did very little code change. In addition, our existing tests did not break and we would just need add tests for the extended functionality. Would this approach allow parallel development? Well, I am in two camps on parallel development but with some planning ahead of time it would allow for it as you would simply need to decide on the interface signature and could then have teams develop different sections programming to that interface. So,this was really just a quick intro to some of the basic concepts of DI that Mark introduces very successfully in his book. I am hoping to blog about this further as I continue through the book to list some of the more complex implementations of containers.

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  • What Counts for a DBA: Skill

    - by drsql
    “Practice makes perfect:” right? Well, not exactly. The reality of it all is that this saying is an untrustworthy aphorism. I discovered this in my “younger” days when I was a passionate tennis player, practicing and playing 20+ hours a week. No matter what my passion level was, without some serious coaching (and perhaps a change in dietary habits), my skill level was never going to rise to a level where I could make any money at the sport that involved something other than selling tennis balls at a sporting goods store. My game may have improved with all that practice but I had too many bad practices to overcome. Practice by itself merely reinforces what we know and what we can figure out naturally. The truth is actually closer to the expression used by Vince Lombardi: “Perfect practice makes perfect.” So how do you get to become skilled as a DBA if practice alone isn’t sufficient? Hit the Internet and start searching for SQL training and you can find 100 different sites. There are also hundreds of blogs, magazines, books, conferences both onsite and virtual. But then how do you know who is good? Unfortunately often the worst guide can be to find out the experience level of the writer. Some of the best DBAs are frighteningly young, and some got their start back when databases were stored on stacks of paper with little holes in it. As a programmer, is it really so hard to understand normalization? Set based theory? Query optimization? Indexing and performance tuning? The biggest barrier often is previous knowledge, particularly programming skills cultivated before you get started with SQL. In the world of technology, it is pretty rare that a fresh programmer will gravitate to database programming. Database programming is very unsexy work, because without a UI all you have are a bunch of text strings that you could never impress anyone with. Newbies spend most of their time building UIs or apps with procedural code in C# or VB scoring obvious interesting wins. Making matters worse is that SQL programming requires mastery of a much different toolset than most any mainstream programming skill. Instead of controlling everything yourself, most of the really difficult work is done by the internals of the engine (written by other non-relational programmers…we just can’t get away from them.) So is there a golden road to achieving a high skill level? Sadly, with tennis, I am pretty sure I’ll never discover it. However, with programming it seems to boil down to practice in applying the appropriate techniques for whatever type of programming you are doing. Can a C# programmer build a great database? As long as they don’t treat SQL like C#, absolutely. Same goes for a DBA writing C# code. None of this stuff is rocket science, as long as you learn to understand that different types of programming require different skill sets and you as a programmer must recognize the difference between one of the procedural languages and SQL and treat them differently. Skill comes from practicing doing things the right way and making “right” a habit.

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  • Get More Value From Your Oracle Premier Support Investment

    - by Get Proactive Customer Adoption Team
    Untitled Document The Return on Investment in Support Training I’m a typical software user. I’ve been using spreadsheets almost daily for the past 10 years or so. I know how to enter simple formulas, format cells, import files, and I can sort and filter. Sometimes I even use a pivot table. I never attended training. I learnt everything I know on the fly. Sometimes it was intuitive and easy, other times I had to spend minutes and even hours searching for a solution. Yet when I see what some other people can do with their spreadsheets, I know I’m utilizing maybe 15% of the functionality. Pity, one day I really have to sign up for training. Why haven’t I done it yet? Ah, you know, I’m a busy person, I have work to do. And if I need to use a feature that I am unfamiliar with, I’ll spend time on it only when I really need it. Now wait. When I recall how much time I spent trying to figure how things work compared to time I spent doing the productive work, I realize it was not insignificant. I’m unable to sum up all the time I spent ‘learning’ on the fly, but I’m sure it’s been days or even weeks. And after all this time, I’ve mastered 15% of its features. If only I had attended training years ago. That investment would have paid back 10 times! Working with My Oracle Support is no different. Our customers typically use simple search, create service requests, and download patches. They think they know how to use My Oracle Support. And they’re right. They know something but often they’re utilizing only a fragment of My Oracle Support’s potential. For the investment that has been made, using only a small subset of the capabilities offered in My Oracle Support leaves value on the table. There is much more available in My Oracle Support. Dozens of diagnostic tools and proactive health checks will keep verifying your Oracle environments against best practices that Oracle gathers every day thanks to our comprehensive knowledge management process. Automated patch recommendations will help prevent known issues, and upgrade planning and more is included in My Oracle Support. Why are you not utilizing all of these best practices, capabilities and tools? Is it because you don’t have time to invest 2-3 hours of your time to learn about the features? Simply because you think you can learn on the fly like I thought I could? Does learning on the fly how to properly use the Service Request escalation process when you already have critical issue sound like a good idea? My advice is: Invest your time now to learn how My Oracle Support can help you prevent issues on your systems. Learn how to find answers faster and resolve problems more efficiently. Understand how to properly complete a service request. Invest in Support training, offered at no additional cost to Oracle Premier Support customers. It will pay back quicker than you think. It will bring you more value than you think. Discover your advantage with Oracle Premier Support's Proactive Portfolio.

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  • Collision 2D Quads

    - by Vico Pelaez
    I want to detect collision between two 2D squares, one square is static and the other one moves according to keyboard arrows. I have implemented some code, however nothing happens when they overlap each other and what I tried to achieve in the code was to detect an overlapping between them. I think I am either not understanding the concept really well or that because one of the squares is moving this is not working. Please I would really appreciate your help. Thank you! float x1=0.05 ,Y1=0.05; float x2=0.05 ,Y2=0.05; float posX1 =0.5, posY1 = 0.5; float movX2 = 0.0 , movY2 = 0.0; struct box{ int width=0.1; int heigth=0.1; }; void init(){ glClearColor(0.0, 0.0, 0.0, 0.0); glColor3f(1.0, 1.0, 1.0); } void quad1(){ glTranslatef(posX1, posY1, 0.0); glBegin(GL_POLYGON); glColor3f(0.5, 1.0, 0.5); glVertex2f(-x1, -Y1); glVertex2f(-x1, Y1); glVertex2f(x1,Y1); glVertex2f(x1,-Y1); glEnd(); } void quad2(){ glMatrixMode(GL_PROJECTION); glLoadIdentity(); glPushMatrix(); glTranslatef(movX2, movY2, 0.0); glBegin(GL_POLYGON); glColor3f(1.5, 1.0, 0.5); glVertex2f(-x2, -Y2); glVertex2f(-x2, Y2); glVertex2f(x2,Y2); glVertex2f(x2,-Y2); glEnd(); glPopMatrix(); } void reset(){ //Reset position of square??? movX2 = 0.0; movY2 = 0.0; collisionB = false; } bool collision(box A, box B){ int leftA, leftB; int rightA, rightB; int topA, topB; int bottomA, bottomB; //Calculate the sides of box A leftA = x1; rightA = x1 + A.width; topA = Y1; bottomA = Y1 + A.heigth; //Calculate the sides of box B leftB = x2; rightB = x2 + B.width; topB = Y1; bottomB = Y1+ B.heigth ; if( bottomA <= topB ) return false; if( topA >= bottomB ) return false; if( rightA <= leftB ) return false; if( leftA >= rightB ) return false; return true; } float move_unit = 0.1; void keyboardown(int key, int x, int y) { switch (key){ case GLUT_KEY_UP: movY2 += move_unit; break; case GLUT_KEY_RIGHT: movX2 += move_unit; break; case GLUT_KEY_LEFT: movX2 -= move_unit; break; case GLUT_KEY_DOWN: movY2 -= move_unit; break; default: break; } glutPostRedisplay(); } void display(){ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); cuad1(); if (!collision) { cuad2(); } else{ reset(); } glFlush(); } int main(int argc, char** argv){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500,500); glutInitWindowPosition(0, 0); glutCreateWindow("Collision Practice"); glutSpecialFunc(keyboardown); glutDisplayFunc(display); init(); glutMainLoop(); }

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  • Pulling My Hair Out - PHP Forms [migrated]

    - by Joe Turner
    Hello and good morning to all. This is my second post on this subject because the first time, things still didn't work and I have now literally been trying to solve this for about 4/5 days straight... I have a file, called 'edit.php', in this file is a form; <?php $company = $_POST["company"]; $phone = $_POST["phone"]; $colour = $_POST["colour"]; $email = $_POST["email"]; $website = $_POST["website"]; $video = $_POST["video"]; $image = $_POST["image"]; $extension = $_POST["extension"]; ?> <form method="post" action="generate.php"><br> <input type="text" name="company" placeholder="Company Name" /><br> <input type="text" name="slogan" placeholder="Slogan" /><br> <input class="color {required:false}" name="colour" placeholder="Company Colour"><br> <input type="text" name="phone" placeholder="Phone Number" /><br> <input type="text" name="email" placeholder="Email Address" /><br> <input type="text" name="website" placeholder="Full Website - Include http://" /><br> <input type="text" name="video" placeholder="Video URL" /><br> <input type="submit" value="Generate QuickLinks" style="background:url(images/submit.png) repeat-x; color:#FFF"/> </form> Then, when the form is submitted, it creates a file using the variables that have been input. The fields that have been filled in go on to become links, I need to be able to say 'if a field is left blank, then put 'XXX' in as a default value'. Does anyone have any ideas? I really think I have tried everything. I'll put below a snippet from the .php file that generates the links... <?php $File = "includes/details.php"; $Handle = fopen($File, 'w'); ?> <?php $File = "includes/details.php"; $Handle = fopen($File, 'w'); $Data = "<div id='logo'> <img width='270px' src='images/logo.png'/img> <h1 style='color:#$_POST[colour]'>$_POST[company]</h1> <h2>$_POST[slogan]</h2> </div> <ul> <li><a class='full-width button' href='tel:$_POST[phone]'>Phone Us</a></li> <li><a class='full-width button' href='mailto:$_POST[email]'>Email Us</a></li> <li><a class='full-width button' href='$_POST[website]'>View Full Website</a></li> <li><a class='full-width button' href='$_POST[video]'>Watch Us</a></li> </ul> \n"; I really do look forward to any response...

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  • Hopping/Tumbling Windows Could Introduce Latency.

    This is a pre-article to one I am going to be writing on adjusting an event’s time and duration to satisfy business process requirements but it is one that I think is really useful when understanding the way that Hopping/Tumbling windows work within StreamInsight.  A Tumbling window is just a special shortcut version of  a Hopping window where the width of the window is equal to the size of the hop Here is the simplest and often used definition for a Hopping Window.  You can find them all here public static CepWindowStream<CepWindow<TPayload>> HoppingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     TimeSpan hopSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   And here is the definition for a Tumbling Window public static CepWindowStream<CepWindow<TPayload>> TumblingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   These methods allow you to group events into windows of a temporal size.  It is a really useful and simple feature in StreamInsight.  One of the downsides though is that the windows cannot be flushed until an event in a following window occurs.  This means that you will potentially never see some events or see them with a delay.  Let me explain. Remember that a stream is a potentially unbounded sequence of events. Events in StreamInsight are given a StartTime.  It is this StartTime that is used to calculate into which temporal window an event falls.  It is best practice to assign a timestamp from the source system and not one from the system clock on the processing server.  StreamInsight cannot know when a window is over.  It cannot tell whether you have received all events in the window or whether some events have been delayed which means that StreamInsight cannot flush the stream for you.   Imagine you have events with the following Timestamps 12:10:10 PM 12:10:20 PM 12:10:35 PM 12:10:45 PM 11:59:59 PM And imagine that you have defined a 1 minute Tumbling Window over this stream using the following syntax var HoppingStream = from shift in inputStream.TumblingWindow(TimeSpan.FromMinutes(1),HoppingWindowOutputPolicy.ClipToWindowEnd) select new WindowCountPayload { CountInWindow = (Int32)shift.Count() };   The events between 12:10:10 PM and 12:10:45 PM will not be seen until the event at 11:59:59 PM arrives.  This could be a real problem if you need to react to windows promptly This can always be worked around by using a different design pattern but a lot of the examples I see assume there is a constant, very frequent stream of events resulting in windows always being flushed. Further examples of using windowing in StreamInsight can be found here

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  • "The connection has timed out" - Please help!

    - by gon
    I recently installed a fresh Ubuntu 12.04 LTS on a desktop, and the installation itself was successful (other than 'grub rescue' issue that I encountered but fixed) but this connection problem is really giving me a headache. Symptoms: 1. When I open the FireFox browser and try to connect to a website, it just hangs for a while saying "Connecting..." but eventually loads an error page "The connection has timed out". 2. It's not a browser problem (and I tried setting ipv6 thing to "true" at about:config) because running "sudo apt-get install [some-random-package]" at terminal fails ("E: Unable to locate package [package]") too. All other operations that need internet access are not working. 3. I certainly see a wired network (called "eth1") at the Network Manager, and it says "Connection Established" after disconnecting and then connecting again. I have tried almost everything that could be found from google search results still no luck. Their problems slightly differ from mine or the solutions just don't work. By the way it didn't have internet access when installing Ubuntu 12.04. (I ignored the message that I need internet to install Ubuntu) Could this be a problem? I'm sorry I don't remember if internet worked or not on the previous version of Ubuntu. :( I would really appreciate your help... I don't even know what more to do if this fails too.. Thanks!! Thanks for your comment. Here is the result of ifconfig: eth0 Link encap:Ethernet HWaddr 78:ac:c0:3d:b2:b9 inet addr:10.10.65.185 Bcast:10.10.65.255 Mask:255.255.255.0 inet6 addr: fe80::7aac:c0ff:fe3d:b2b9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:3907 errors:0 dropped:0 overruns:0 frame:0 TX packets:771 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:393118 (393.1 KB) TX bytes:73472 (73.4 KB) Interrupt:16 eth1 Link encap:Ethernet HWaddr 78:ac:c0:3d:b2:b8 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) 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:16436 Metric:1 RX packets:4 errors:0 dropped:0 overruns:0 frame:0 TX packets:4 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:204 (204.0 B) TX bytes:204 (204.0 B) route -n: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.10.65.1 0.0.0.0 UG 0 0 0 eth0 10.10.65.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 /etc/resolv.conf: # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 8.8.8.8 nameserver 8.8.4.4 nameserver 10.81.1.8 nameserver 10.1.2.10 nameserver 127.0.0.1 search yamatake.local /etc/network/interfaces: auto lo iface lo inet loopback #auto eth0 #iface eth0 inet dhcp #auto eth1 #iface eth1 inet dhcp And I'll also include the result of 'sudo lshw -C network' in case it might help: *-network description: Ethernet interface product: NetXtreme BCM5764M Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 10 serial: 78:ac:c0:3d:b2:b9 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5764m-v3.35 ip=10.10.65.185 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resources: irq:93 memory:fc000000-fc00ffff *-network description: Ethernet interface product: NetXtreme BCM5764M Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:01:00.0 logical name: eth1 version: 10 serial: 78:ac:c0:3d:b2:b8 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5764m-v3.35 latency=0 link=no multicast=yes port=twisted pair speed=100Mbit/s resources: irq:94 memory:fb000000-fb00ffff

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  • Use a custom value object or a Guid as an entity identifier in a distributed system?

    - by Kazark
    tl;dr I've been told that in domain-driven design, an identifier for an entity could be a custom value object, i.e. something other than Guid, string, int, etc. Can this really be advisable in a distributed system? Long version I will invent an situation analogous to the one I am currently facing. Say I have a distributed system in which a central concept is an egg. The system allows you to order eggs and see spending reports and inventory-centric data such as quantity on hand, usage, valuation and what have you. There area variety of services backing these behaviors. And say there is also another app which allows you to compose recipes that link to a particular egg type. Now egg type is broken down by the species—ostrich, goose, duck, chicken, quail. This is fine and dandy because it means that users don't end up with ostrich eggs when they wanted quail eggs and whatnot. However, we've been getting complaints because jumbo chicken eggs are not even close to equivalent to small ones. The price is different, and they really aren't substitutable in recipes. And here we thought we were doing users a favor by not overwhelming them with too many options. Currently each of the services (say, OrderSubmitter, EggTypeDefiner, SpendingReportsGenerator, InventoryTracker, RecipeCreator, RecipeTracker, or whatever) are identifying egg types with an industry-standard integer representation the species (let's call it speciesCode). We realize we've goofed up because this change could effect every service. There are two basic proposed solutions: Use a predefined identifier type like Guid as the eggTypeID throughout all the services, but make EggTypeDefiner the only service that knows that this maps to a speciesCode and eggSizeCode (and potentially to an isOrganic flag in the future, or whatever). Use an EggTypeID value object which is a combination of speciesCode and eggSizeCode in every service. I've proposed the first solution because I'm hoping it better encapsulates the definition of what an egg type is in the EggTypeDefiner and will be more resilient to changes, say if some people now want to differentiate eggs by whether or not they are "organic". The second solution is being suggested by some people who understand DDD better than I do in the hopes that less enrichment and lookup will be necessary that way, with the justification that in DDD using a value object as an ID is fine. Also, they are saying that EggTypeDefiner is not a domain and EggType is not an entity and as such should not have a Guid for an ID. However, I'm not sure the second solution is viable. This "value object" is going to have to be serialized into JSON and URLs for GET requests and used with a variety of technologies (C#, JavaScript...) which breaks encapsulation and thus removes any behavior of the identifier value object (is either of the fields optional? etc.) Is this a case where we want to avoid something that would normally be fine in DDD because we are trying to do DDD in a distributed fashion? Summary Can it be a good idea to use a custom value object as an identifier in a distributed system (solution #2)?

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  • Broken Views

    - by Ajarn Mark Caldwell
    “SELECT *” isn’t just hazardous to performance, it can actually return blatantly wrong information. There are a number of blog posts and articles out there that actively discourage the use of the SELECT * FROM …syntax.  The two most common explanations that I have seen are: Performance:  The SELECT * syntax will return every column in the table, but frequently you really only need a few of the columns, and so by using SELECT * your are retrieving large volumes of data that you don’t need, but the system has to process, marshal across tiers, and so on.  It would be much more efficient to only select the specific columns that you need. Future-proof:  If you are taking other shortcuts in your code, along with using SELECT *, you are setting yourself up for trouble down the road when enhancements are made to the system.  For example, if you use SELECT * to return results from a table into a DataTable in .NET, and then reference columns positionally (e.g. myDataRow[5]) you could end up with bad data if someone happens to add a column into position 3 and skewing all the remaining columns’ ordinal position.  Or if you use INSERT…SELECT * then you will likely run into errors when a new column is added to the source table in any position. And if you use SELECT * in the definition of a view, you will run into a variation of the future-proof problem mentioned above.  One of the guys on my team, Mike Byther, ran across this in a project we were doing, but fortunately he caught it while we were still in development.  I asked him to put together a test to prove that this was related to the use of SELECT * and not some other anomaly.  I’ll walk you through the test script so you can see for yourself what happens. We are going to create a table and two views that are based on that table, one of them uses SELECT * and the other explicitly lists the column names.  The script to create these objects is listed below. IF OBJECT_ID('testtab') IS NOT NULL DROP TABLE testtabgoIF OBJECT_ID('testtab_vw') IS NOT NULL DROP VIEW testtab_vwgo IF OBJECT_ID('testtab_vw_named') IS NOT NULL DROP VIEW testtab_vw_namedgo CREATE TABLE testtab (col1 NVARCHAR(5) null, col2 NVARCHAR(5) null)INSERT INTO testtab(col1, col2)VALUES ('A','B'), ('A','B')GOCREATE VIEW testtab_vw AS SELECT * FROM testtabGOCREATE VIEW testtab_vw_named AS SELECT col1, col2 FROM testtabgo Now, to prove that the two views currently return equivalent results, select from them. SELECT 'star', col1, col2 FROM testtab_vwSELECT 'named', col1, col2 FROM testtab_vw_named OK, so far, so good.  Now, what happens if someone makes a change to the definition of the underlying table, and that change results in a new column being inserted between the two existing columns?  (Side note, I normally prefer to append new columns to the end of the table definition, but some people like to keep their columns alphabetized, and for clarity for later people reviewing the schema, it may make sense to group certain columns together.  Whatever the reason, it sometimes happens, and you need to protect yourself and your code from the repercussions.) DROP TABLE testtabgoCREATE TABLE testtab (col1 NVARCHAR(5) null, col3 NVARCHAR(5) NULL, col2 NVARCHAR(5) null)INSERT INTO testtab(col1, col3, col2)VALUES ('A','C','B'), ('A','C','B')goSELECT 'star', col1, col2 FROM testtab_vwSELECT 'named', col1, col2 FROM testtab_vw_named I would have expected that the view using SELECT * in its definition would essentially pass-through the column name and still retrieve the correct data, but that is not what happens.  When you run our two select statements again, you see that the View that is based on SELECT * actually retrieves the data based on the ordinal position of the columns at the time that the view was created.  Sure, one work-around is to recreate the View, but you can’t really count on other developers to know the dependencies you have built-in, and they won’t necessarily recreate the view when they refactor the table. I am sure that there are reasons and justifications for why Views behave this way, but I find it particularly disturbing that you can have code asking for col2, but actually be receiving data from col3.  By the way, for the record, this entire scenario and accompanying test script apply to SQL Server 2008 R2 with Service Pack 1. So, let the developer beware…know what assumptions are in effect around your code, and keep on discouraging people from using SELECT * syntax in anything but the simplest of ad-hoc queries. And of course, let’s clean up after ourselves.  To eliminate the database objects created during this test, run the following commands. DROP TABLE testtabDROP VIEW testtab_vwDROP VIEW testtab_vw_named

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  • Identity in .NET 4.5&ndash;Part 3: (Breaking) changes

    - by Your DisplayName here!
    I recently started porting a private build of Thinktecture.IdentityModel to .NET 4.5 and noticed a number of changes. The good news is that I can delete large parts of my library because many features are now in the box. Along the way I found some other nice additions. ClaimsIdentity now has methods to query the claims collection, e.g. HasClaim(), FindFirst(), FindAll(). ClaimsPrincipal has those methods as well. But they work across all contained identities. Nice! ClaimsPrincipal.Current retrieves the ClaimsPrincipal from Thread.CurrentPrincipal. Combined with the above changes, no casting necessary anymore. SecurityTokenHandler now has read and write methods that work directly with strings. This makes it much easier to deal with non-XML tokens like SWT or JWT. A new session security token handler that uses the ASP.NET machine key to protect the cookie. This makes it easier to get started in web farm scenarios. No need for a custom service host factory or the federation behavior anymore. WCF can be switched into “WIF mode” with the useIdentityConfiguration switch (odd name though). Tooling has become better and the new test STS makes it very easy to get started. On the other hand – and that was kind of expected – to bring claims into the core framework, there are also some breaking changes for WIF code. If you want to migrate (and I would recommend that), most changes to your code are mechanical. The following is a brain dump of the changes I encountered. Assembly Microsoft.IdentityModel is gone. The new functionality is now in mscorlib, System.IdentityModel(.Services) and System.ServiceModel. All the namespaces have changed as well. No IClaimsPrincipal and IClaimsIdentity anymore. Configuration section has been split into <system.identityModel /> and <system.identityModel.services />. WCF configuration story has changed as well. Claim.ClaimType is now Claim.Type. ClaimCollection is now IEnumerable<Claim>. IsSessionMode is now IsReferenceMode. Bootstrap token handling is different now. ClaimsPrincipalHttpModule is gone. This is not really needed anymore, apart from maybe claims transformation (see here). Various factory methods on ClaimsPrincipal are gone (e.g. ClaimsPrincipal.CreateFromIdentity()). SecurityTokenHandler.ValidateToken now returns a ReadOnlyCollection<ClaimsIdentity>. Some lower level helper classes are gone or internal now (e.g. KeyGenerator). The WCF WS-Trust bindings are gone. I think this is a pity. They were *really* useful when doing work with WSTrustChannelFactory. Since WIF is part of the Windows operating system and also supported in future versions of .NET, there is no urgent need to migrate to the 4.5 claims model. But obviously, going forward, at some point you want to make the move.

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  • Why is the framerate (fps) capped at 60?

    - by dennmat
    ISSUE I recently moved a project from my laptop to my desktop(machine info below). On my laptop the exact same code displays the fps(and ms/f) correctly. On my desktop it does not. What I mean by this is on the laptop it will display 300 fps(for example) where on my desktop it will show only up to 60. If I add 100 objects to the game on the laptop I'll see my frame rate drop accordingly; the same test on the desktop results in no change and the frames stay at 60. It takes a lot(~300) entities before I'll see a frame drop on the desktop, then it will descend. It seems as though its "theoretical" frames would be 400 or 500 but will never actually get to that and only do 60 until there's too much to handle at 60. This 60 frame cap is coming from no where. I'm not doing any frame limiting myself. It seems like something external is limiting my loop iterations on the desktop, but for the last couple days I've been scratching my head trying to figure out how to debug this. SETUPS Desktop: Visual Studio Express 2012 Windows 7 Ultimate 64-bit Laptop: Visual Studio Express 2010 Windows 7 Ultimate 64-bit The libraries(allegro, box2d) are the same versions on both setups. CODE Main Loop: while(!abort) { frameTime = al_get_time(); if (frameTime - lastTime >= 1.0) { lastFps = fps/(frameTime - lastTime); lastTime = frameTime; avgMspf = cumMspf/fps; cumMspf = 0.0; fps = 0; } /** DRAWING/UPDATE CODE **/ fps++; cumMspf += al_get_time() - frameTime; } Note: There is no blocking code in the loop at any point. Where I'm at My understanding of al_get_time() is that it can return different resolutions depending on the system. However the resolution is never worse than seconds, and the double is represented as [seconds].[finer-resolution] and seeing as I'm only checking for a whole second al_get_time() shouldn't be responsible. My project settings and compiler options are the same. And I promise its the same code on both machines. My googling really didn't help me much, and although technically it's not that big of a deal. I'd really like to figure this out or perhaps have it explained, whichever comes first. Even just an idea of how to go about figuring out possible causes, because I'm out of ideas. Any help at all is greatly appreciated. EDIT: Thanks All. For any others that find this to disable vSync(windows only) in opengl: First get "wglext.h". It's all over the web. Then you can use a tool like GLee or just write your own quick extensions manager like: bool WGLExtensionSupported(const char *extension_name) { PFNWGLGETEXTENSIONSSTRINGEXTPROC _wglGetExtensionsStringEXT = NULL; _wglGetExtensionsStringEXT = (PFNWGLGETEXTENSIONSSTRINGEXTPROC) wglGetProcAddress("wglGetExtensionsStringEXT"); if (strstr(_wglGetExtensionsStringEXT(), extension_name) == NULL) { return false; } return true; } and then create and setup your function pointers: PFNWGLSWAPINTERVALEXTPROC wglSwapIntervalEXT = NULL; PFNWGLGETSWAPINTERVALEXTPROC wglGetSwapIntervalEXT = NULL; if (WGLExtensionSupported("WGL_EXT_swap_control")) { // Extension is supported, init pointers. wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC) wglGetProcAddress("wglSwapIntervalEXT"); // this is another function from WGL_EXT_swap_control extension wglGetSwapIntervalEXT = (PFNWGLGETSWAPINTERVALEXTPROC) wglGetProcAddress("wglGetSwapIntervalEXT"); } Then just call wglSwapIntervalEXT(0) to disable vSync and 1 to enable vSync. I found the reason this is windows only is that openGl actually doesn't deal with anything other than rendering it leaves the rest up to the OS and Hardware. Thanks everyone saved me a lot of time!

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  • How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

    - by Register Sole
    Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based method with Projected-Gauss-Seidel (PGS) iterative solver as described by Erin Catto (mentioned in the reference of the paper as [Catt05]). So here's how it currently is: The simulation handles 2-dimensional rotating convex polygons. Detection is using separating-axis test, with a SKIN, meaning closest points between two polygons is detected and determined if their distance is less than SKIN. To resolve collision, simultaneous impulse-based method is used. It is solved using iterative solver (PGS-solver) as in Erin Catto's paper. Error-correction is implemented using Baumgarte's stabilization (you can refer to either paper for this) using J V = beta/dt*overlap, J is the Jacobian for the constraints, V the matrix containing the velocities of the bodies, beta an error-correction parameter that is better be < 1, dt the time-step taken by the engine, and overlap, the overlap between the bodies (true overlap, so SKIN is ignored). However, it is still less stable than I expected :s I tried to stack hexagons (or squares, doesn't really matter), and even with only 4 to 5 of them, they would swing! Also note that I am not looking for a sleeping scheme. But I would settle if you have any explicit scheme to handle resting contacts. That said, I would be more than happy if you have a way of treating it generally (as continuous collision, instead of explicitly as a special state). Ideas I have tried: Using simultaneous position based error correction as described in the paper in section 5.3.2, turned out to be worse than the current scheme. If you want to know the parameters I used: Hexagons, side 50 (pixels) gravity 2400 (pixels/sec^2) time-step 1/60 (sec) beta 0.1 restitution 0 to 0.2 coeff. of friction 0.2 PGS iteration 10 initial separation 10 (pixels) mass 1 (unit is irrelevant for now, i modified velocity directly<-impulse method) inertia 1/1000 Thanks in advance! I really appreciate any help from you guys!! :) EDIT In response to Cholesky's comment about warm starting the solver and Baumgarte: Oh right, I forgot to mention! I do save the contact history and the impulse determined in this time step to be used as initial guess in the next time step. As for the Baumgarte, here's what actually happens in the code. Collision is detected when the bodies' closest distance is less than SKIN, meaning they are actually still separated. If at this moment, I used the PGS solver without Baumgarte, restitution of 0 alone would be able to stop the bodies, separated by a distance of ~SKIN, in mid-air! So this isn't right, I want to have the bodies touching each other. So I turn on the Baumgarte, where its role is actually to pull the bodies together! Weird I know, a scheme intended to push the body apart becomes useful for the reverse. Also, I found that if I increase the number of iteration to 100, stacks become much more stable, though the program becomes so slow. UPDATE Since the stack swings left and right, could it be something is wrong with my friction model? Current friction constraint: relative_tangential_velocity = 0

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  • No access to Samba shares

    - by koanhead
    I have three shared folders in my local home directory- that is to say, on my Ubuntu desktop's /home/me/. All were set up using "Sharing Options" in Nautilus' right-click menu. The standard "Music" and "Videos" folders are configured identically: the "Guest Access" box is checked, but the "Allow others to create and delete" is not. The third folder, called "shared", is configured to not allow Guest access but to allow others to modify files. I have not altered /etc/samba/smb.conf by hand, I have only used Sharing Options to create and modify these so-called "shares". My roommates have two Windows 7 computers and one Ubuntu Netbook Remix netbook. I have the aforementioned desktop machine and laptop running 10.04. None of these machines can access any of the shares. Attempts to access the Guest shares result in the message \\machine\directory is not accessible. The network name could not be found. This is the error message generated by a VM running Windows 2000. The other Windows machines generate a similar error. The Ubuntu laptop gives the error Unable to mount location: Failed to mount Windows share. Hurrah, once again, for informative error messages. That really helps a lot. When attempting to browse the folder called "shared" from the laptop, I'm confronted with a password dialog. This behavior is the same will all machines I've tried in the situation. On entering my username and password for the account to which the shares belong, the password dialog briefly disappears and is replaced with an identical dialog. No error message, useful or not, appears. When attempting to browse this folder with the VM, the outcome is the same except that the password dialog helpfully states "incorrect username or password". My assumption is that the username and password in question is that of the user which owns the shares. I have tried all other username and password combinations available in this context and the outcome is the same. I would like to be able to share files. Sharing them with Windows machines is a nice feature, or would be if it was available. Really I consider sharing files between two machines with the same version of the same operating system kind of a minimum condition for network usability. Samba last functioned reliably for me more than ten years ago. I have attempted to use it on and off since then with only intermittent success. Oh, and "Personal File Sharing" from the Preferences menu does not result in an entry in Places → Network → my-server. In fact, the old entry "MY-SERVER" goes away and is replaced by "koanhead's public files on my-server", which when I attempt to open it from the laptop gives a "DBus.Error.NoReply: Message did not receive a reply." I know I come here and gripe about Ubuntu a lot, but on the other hand I spend literally hours every day trying to fix things in Ubuntu. It's a good system which aspires to greatness, which is why things like this either Need to work; or Be adequately documented. Ideally both would be the case. Anyway, rant over. Hopefully someone will have some insight on this issue. Thanks all who bother to read this wall o'text for your time.

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  • Software and/(x)or Hardware Projects for Pre-School Kids

    - by haylem
    I offered to participate at my kid's pre-school for various activities (yes, I'm crazy like that), and one of them is to help them discover extra-curricular (big word for a pre-school, but by lack of a better one... :)) hobbies, which may or may not relate to a professional activity. At first I thought that it wouldn't be really easy to have pre-schoolers relate to programming or the internal workings of a computer system in general (and I'm more used to teaching middle-school to university-level students), but then I thought there must be a way. So I'm trying to figure out ways to introduce very young kids (3yo) to computer systems in a fun and preferably educational way. Of course, I don't expect them to start smashing the stack for fun and profit right away (or at least not voluntarily, though I could use the occasion for some toddler tests...), but I'm confident there must be ways to get them interested in both: using the systems, becoming curious about understanding what they do, interacting with the systems to modify them. I guess this setting is not really relevant after all, it's pretty much the same as if you were aiming to achieve the same for your own kids at home. Ideas Considering we're talking 3yo pre-schoolers here, and that at this age some kids are already quite confident using a mouse (some even a keyboard, if not for typing, at least to press some buttons they've come to associate with actions) while others have not yet had any interaction with computers of any kind, it needs to be: rather basic, demonstrated and played with in less then 5 or 10 minutes, doable in in groups or alone, scalable and extendable in complexity to accommodate their varying abilities. The obvious options are: basic smallish games to play with, interactive systems like LOGO, Kojo, Squeak and clones (possibly even simpler than that), or thngs like Lego Systems. I guess it can be a thing to reflect on both at the software and the hardware levels: it could be done with a desktop or laptop machine, a tablet, a smartphone (or a crap-phone, for that matter, as long as you can modify it), or even get down to building something from scratch (Raspberry Pi and Arduino being popular options at the moment). I can probably be in the form of games, funny visualizations (which are pretty much games) w/ Prototype, virtual worlds to explore. I also thought on the moment (and I hope this won't offend anyone) that some approaches to teaching pets could work (reward systems, haptic feedback and such things could quickly point a kid in the right direction to understanding how things work, in a similar fashion - I'm not suggesting to shock the kids!). Hmm, Is There an Actual Question in There? What type of systems do you think might be a good fit, both in terms of hardware and software? Do you have seen such systems, or have anything in mind to work on? Are you aware of some research in this domain, with tangible results? Any input is welcome. It's not that I don't see options: there are tons, but I have a harder time pinpointing a more concrete and definite type of project/activity, so I figure some have valuable ideas or existing ones. Note: I am not advocating that every kid should learn to program, be interested in computer systems, or that all of them in a class would even care enough to follow such an introduction with more than a blank stare. I don't buy into the "everybody would benefit from learning to program" thing. Wouldn't hurt, but not necessary in any way. But if I can walk out of there with a few of them having smiled using the thing (or heck, cried because others took them away from them), that'd be good enough. Related Questions I've seen and that seem to complement what I'm looking for, but not exactly for the same age groups or with the same goals: Teaching Programming to Kids Recommendations for teaching kids math concepts & skills for programming?

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  • Getting 2D Platformer entity collision Response Correct (side-to-side + jumping/landing on heads)

    - by jbrennan
    I've been working on a 2D (tile based) 2D platformer for iOS and I've got basic entity collision detection working, but there's just something not right about it and I can't quite figure out how to solve it. There are 2 forms of collision between player entities as I can tell, either the two players (human controlled) are hitting each other side-to-side (i. e. pushing against one another), or one player has jumped on the head of the other player (naturally, if I wanted to expand this to player vs enemy, the effects would be different, but the types of collisions would be identical, just the reaction should be a little different). In my code I believe I've got the side-to-side code working: If two entities press against one another, then they are both moved back on either side of the intersection rectangle so that they are just pushing on each other. I also have the "landed on the other player's head" part working. The real problem is, if the two players are currently pushing up against each other, and one player jumps, then at one point as they're jumping, the height-difference threshold that counts as a "land on head" is passed and then it registers as a jump. As a life-long player of 2D Mario Bros style games, this feels incorrect to me, but I can't quite figure out how to solve it. My code: (it's really Objective-C but I've put it in pseudo C-style code just to be simpler for non ObjC readers) void checkCollisions() { // For each entity in the scene, compare it with all other entities (but not with one it's already compared against) for (int i = 0; i < _allGameObjects.count(); i++) { // GameObject is an Entity GEGameObject *firstGameObject = _allGameObjects.objectAtIndex(i); // Don't check against yourself or any previous entity for (int j = i+1; j < _allGameObjects.count(); j++) { GEGameObject *secondGameObject = _allGameObjects.objectAtIndex(j); // Get the collision bounds for both entities, then see if they intersect // CGRect is a C-struct with an origin Point (x, y) and a Size (w, h) CGRect firstRect = firstGameObject.collisionBounds(); CGRect secondRect = secondGameObject.collisionBounds(); // Collision of any sort if (CGRectIntersectsRect(firstRect, secondRect)) { //////////////////////////////// // // // Check for jumping first (???) // // //////////////////////////////// if (firstRect.origin.y > (secondRect.origin.y + (secondRect.size.height * 0.7))) { // the top entity could be pretty far down/in to the bottom entity.... firstGameObject.didLandOnEntity(secondGameObject); } else if (secondRect.origin.y > (firstRect.origin.y + (firstRect.size.height * 0.7))) { // second entity was actually on top.... secondGameObject.didLandOnEntity.(firstGameObject); } else if (firstRect.origin.x > secondRect.origin.x && firstRect.origin.x < (secondRect.origin.x + secondRect.size.width)) { // Hit from the RIGHT CGRect intersection = CGRectIntersection(firstRect, secondRect); // The NUDGE just offsets either object back to the left or right // After the nudging, they are exactly pressing against each other with no intersection firstGameObject.nudgeToRightOfIntersection(intersection); secondGameObject.nudgeToLeftOfIntersection(intersection); } else if ((firstRect.origin.x + firstRect.size.width) > secondRect.origin.x) { // hit from the LEFT CGRect intersection = CGRectIntersection(firstRect, secondRect); secondGameObject.nudgeToRightOfIntersection(intersection); firstGameObject.nudgeToLeftOfIntersection(intersection); } } } } } I think my collision detection code is pretty close, but obviously I'm doing something a little wrong. I really think it's to do with the way my jumps are checked (I wanted to make sure that a jump could happen from an angle (instead of if the falling player had been at a right angle to the player below). Can someone please help me here? I haven't been able to find many resources on how to do this properly (and thinking like a game developer is new for me). Thanks in advance!

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  • Is hidden content (display: none;) -indexed- by search engines? [closed]

    - by user568458
    Possible Duplicate: How bad is it to use display: none in CSS? We've established on this site before (in this question) that, since there are so many legitimate uses for hiding content with display: none; when creating interactive features, that sites aren't automatically penalised for content that is hidden this way (so long as it doesn't look algorithmically spammy). Google's Webmaster guidelines also make clear that a good practice when using content that is initially legitimately hidden for interactivity purposes is to also include the same content in a <noscript> tag, and Google recommend that if you design and code for users including users with screen readers or javascript disabled, then 9 times out of 10 good relevant search rankings will follow (though their specific advice seems more written for cases where javascript writes new content to the page). JavaScript: Place the same content from the JavaScript in a tag. If you use this method, ensure the contents are exactly the same as what’s contained in the JavaScript, and that this content is shown to visitors who do not have JavaScript enabled in their browser. So, best practice seems pretty clear. What I can't find out is, however, the simple factual matter of whether hidden content is indexed by search engines (but with potential penalties if it looks 'spammy'), or, whether it is ignored, or, whether it is indexed but with a lower weighting (like <noscript> content is, apparently). (for bonus points it would be great to know if this varies or is consistent between display: none;, visibility: hidden;, etc, but that isn't crucial). This is different to the other questions on display:none; and SEO - those are about good and bad practice and the answers are discussions of good and bad practice, I'm interested simply in the factual 'Yes or no' question of whether search engines index, or ignore, content that is in display: none; - something those other questions' answers aren't totally clear on. One other question has an answer, "Yes", supported by a link to an article that doesn't really clear things up: it establishes that search engines can spot that text is hidden, it discusses (again) whether hidden text causes sites to be marked as spam, and ultimately concludes that in mid 2011, Google's policy on hidden text was evolving, and that they hadn't at that time started automatically penalising display:none; or marking it as spam. It's clear that display: none; isn't always spam and isn't always treated as spam (many Google sites use it...): but this doesn't clear up how, or if, it is indexed. What I will do will be to follow the guidelines and make sure that all the content that is initially hidden which regular users can explore using javascript-driven interactivity is also structured in way that noscript/screenreader users can use. So I'm not interested in best practice, opinions etc because best practice seems to be really clear: accessibility best practices boosts SEO. But I'd like to know what exactly will happen: whether any display: none; content I have alongside <noscript> or otherwise accessibility-optimised content will be be ignored, or indexed again, or picked up to compare against the <noscript> content but not indexed... etc.

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  • No access to Samba shares

    - by koanhead
    I have three shared folders in my local home directory- that is to say, on my Ubuntu desktop's /home/me/. All were set up using "Sharing Options" in Nautilus' right-click menu. The standard "Music" and "Videos" folders are configured identically: the "Guest Access" box is checked, but the "Allow others to create and delete" is not. The third folder, called "shared", is configured to not allow Guest access but to allow others to modify files. I have not altered /etc/samba/smb.conf by hand, I have only used Sharing Options to create and modify these so-called "shares". My roommates have two Windows 7 computers and one Ubuntu Netbook Remix netbook. I have the aforementioned desktop machine and laptop running 10.04. None of these machines can access any of the shares. Attempts to access the Guest shares result in the message \\machine\directory is not accessible. The network name could not be found. This is the error message generated by a VM running Windows 2000. The other Windows machines generate a similar error. The Ubuntu laptop gives the error Unable to mount location: Failed to mount Windows share. Hurrah, once again, for informative error messages. That really helps a lot. When attempting to browse the folder called "shared" from the laptop, I'm confronted with a password dialog. This behavior is the same will all machines I've tried in the situation. On entering my username and password for the account to which the shares belong, the password dialog briefly disappears and is replaced with an identical dialog. No error message, useful or not, appears. When attempting to browse this folder with the VM, the outcome is the same except that the password dialog helpfully states "incorrect username or password". My assumption is that the username and password in question is that of the user which owns the shares. I have tried all other username and password combinations available in this context and the outcome is the same. I would like to be able to share files. Sharing them with Windows machines is a nice feature, or would be if it was available. Really I consider sharing files between two machines with the same version of the same operating system kind of a minimum condition for network usability. Samba last functioned reliably for me more than ten years ago. I have attempted to use it on and off since then with only intermittent success. Oh, and "Personal File Sharing" from the Preferences menu does not result in an entry in Places → Network → my-server. In fact, the old entry "MY-SERVER" goes away and is replaced by "koanhead's public files on my-server", which when I attempt to open it from the laptop gives a "DBus.Error.NoReply: Message did not receive a reply." I know I come here and gripe about Ubuntu a lot, but on the other hand I spend literally hours every day trying to fix things in Ubuntu. It's a good system which aspires to greatness, which is why things like this either Need to work; or Be adequately documented. Ideally both would be the case. Anyway, rant over. Hopefully someone will have some insight on this issue. Thanks all who bother to read this wall o'text for your time.

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  • How do you go from a so so programmer to a great one? [closed]

    - by Cervo
    How do you go from being an okay programmer to being able to write maintainable clean code? For example David Hansson was writing Basecamp when in the process he created Rails as part of writing Basecamp in a clean/maintainable way. But how do you know when there is value in a side project like that? I have a bachelors in computer science, and I am about to get a masters and I will say that colleges teach you to write code to solve problems, not neatly or anything. Basically you think of a problem, come up with a solution, and write it down...not necessarily the most maintainable way in the world. Also my first job was in a startup, and now my third is in a small team in a large company where the attitude was/is get it done yesterday (also most of my jobs are mainly database development with SQL with a few ASP.NET web pages/.NET apps on the side). So of course cut/paste is more favored than making things more cleanly. And they would rather have something yesterday even if you have to rewrite it next month rather than to have something in a week that lasts for a year. Also spaghetti code turns up all over the place, and it takes very smart people to write/understand/maintain spaghetti code...However it would be better to do things so simple/clean that even a caveman/woman could do maintenance. Also I get very bored/unmotivated having to go modify the same things cut/pasted in a few locations. Is this the type of skill that you need to learn by working with a serious software organization that has an emphasis on maintenance and maybe even an architect who designs a system architecture and reviews code? Could you really learn it by volunteering on an open source project (it seems to me that a full time programmer job is way more practice than a few hours a week on an open source project)? Is there some course where you can learn this? I can attest that graduate school and undergraduate school do not really emphasize clean software at all. They just teach the structures/algorithms and then send you off into the world to solve problems. Overall I think the first thing is learning to write clean/maintainable code within the bounds of the project in order to become a good programmer. Then the next thing is learning when you need to do a side project (like a framework) to make things more maintainable/clean even while you still deliver things for the deadline in order to become a great programmer. For example, you are making an SQL report and someone gives you 100 calculations for individual columns. At what point does it make sense to construct a domain specific language to encode the rules in simply and then generate all the SQL as opposed to cut/pasting the query from the table a bunch of times and then adjusting each query to do the appropriate calculations. This is the type of thing I would say a great programmer would know. He/she would maybe even know ways to avoid the domain specific language and to still do all the calculations without creating an unmaintainable mess or a ton of repetitive code to cut/paste everywhere.

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  • The new direction of the gaming industry

    - by raccoon_tim
    Just recently I read a great blog post by David Darling, the founder of Codemasters: http://www.develop-online.net/blog/347/Jurassic-consoles-could-become-extinct. In the blog post he talks about how traditional retail games are experiencing a downfall thanks to the increasing popularity of digital distribution. I personally think of retail games as being relics of the past. It does not really make much sense to still keep distributing boxed games when the same game can be elegantly downloaded and updated over the air through a digital distribution channel. The world is not all rainbows, however. One big issue with mixing digital distribution with boxed retail games is that resellers will not condone you selling your game for 10€ digitally while their selling the same game for 70€. The only way to get around this issue is to move to full digital distribution. This has the added benefit of minimizing piracy as the game can be tightly bound to the service you downloaded the game from. Many players are, however, complaining about not being able to play the games offline. Having games tightly bound to the internet is a problem when games are bought from a retailer as we tend to expect that once we have the product we can use it anywhere because we physically own it. The truth is that we don’t actually own the product. Instead, the typical EULA actually states that we only have a license to use the product. We’re not, for instance, allowed to disassemble the product, which the owner is indeed permitted to do. Digital distribution allows us to provide games as services, instead of selling them as standalone products. This means that for a service to work you have to be connected to the internet but you still have the same rights to use the product. It’s really straightforward; if you downloaded a client from the internet you are expected to have an internet connection so you’re able to connect to the server. A game distributed digitally that is built using a client-server architecture has the added benefit of allowing you to play anywhere as long as you have the client installed and you are able to log in with your user information. Your save games can be backed up and your game can continue anywhere. Another development we’re seeing in the gaming industry is the increasing popularity of free-to-play games. These are games that let you play for free but allow you to boost your gaming experience with real world money. The nature of these games is that players are constantly rewarded with new content and the game can evolve according to their way of playing and their wishes can be incorporated into the product. Free-to-play games can quickly gain a large player basis and monetization is done by providing players valuable things to buy making their gaming experience more fun. I am personally very excited about free-to-play games as it’s possible to start building the game together with your players and there is no need to work on the game for 5 years from start to finish and only then see if it’s actually something the players like. This is a typical problem with big movie-like retail games and recent news about Radical Entertainment practically closing its doors paints a clear picture of what can happen when the risk does not pay off: http://news.teamxbox.com/xbox/25874/Prototype-Developer-Radical-Entertainment-Closes/.

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  • My Favorite Free Windows Phone Twitter App

    - by Tim Murphy
    Windows Phone 7 has been out for about two years now.  In that time I have switched back and forth with different free Twitter apps.  Mostly the has been because someone has mentioned one or another that they like.  I figured I would give a quick run down of what I felt were the pros and cons of each.  These are only the ones that I have used and your mileage may vary.  So here we go. WP7 Built-In Twitter Functionality While it is great that Microsoft put this functionality in, it is extremely limited in usefulness.  Some apps leverage it to allow you to share pictures or information they contain.  In all though, I don’t use it unless it is the quickest way to get something out. Official Twitter App The official Twitter app isn’t a very big step up from the phone functionality.  It gives you a better timeline view and better attachment handling, but it makes you bounce to a browser page to see images that are linked to a tweet. TweetCaster This was my main Twitter app for quite a while.  It is the only one with InstaPaper integration so that you can save you a tweet and review it later.  My main problem is that it crashes too much when it can’t find a connection.  It also only previews yfrog and twitpic images and only once you go to the detail of a tweet.  Other than that it is a solid Twitter client. moTweets This is my current favorite. It has nice image display in your timeline which I have not seen on any of the other apps.  There are two modes that you can use with this app.  The first is standard to most Twitter apps that allows you to navigate to a tweet and do the usual operations.  The second is what they call Quick Buttons.  In this case you do not see the content of the tweet but go straight to the let’s get something done stage.  It is an interesting take.  I do miss the Instapaper integration and it has a tendency to show a blank timeline list once in a while after you view detail entry.  If you scroll the list it restore your timeline, but you lose you place and are put to the first entry. Seesmic I am not very fond of this app.  The first thing is that it makes you pick a “Space” when you enter the app.  This is really “which account do you want to see”.  On top of that it does not show who retweeted an entry in your timeline and then only tells you how many people RT the post when you look at the detail.  There is a Speak feature that will read you a single tweet, but you have to navigate to the tweet and then to a menu to make it work.  We will have to see if this gets better with the features in Windows Phone 8.  Other than that it is another basic feature app.  Summary In the end I am sticking with moTweets.  I would appreciate it if they added the Instapaper capability and fixed the one bug.  If they did that I would be really happy with the product. del.icio.us Tags: Twitter,Windows Phone 7,WP7,TweetCaster,moTweets,Seesmic

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  • Qt vs WPF/.NET

    - by aaronc
    My company is trying to make the decision between using Qt/C++ for our GUI framework or migrating to .NET and using WPF. We have up to this point been using MFC. It seems that .NET/WPF is technically the most advanced and feature-rich platform. I do, however, have several concerns. These include: Platform support Framework longevity (i.e. future-proofing) Performance and overhead For this application we are willing to sacrifice support for Windows 2000, Macs, and Linux. But, the issue is more related to Microsoft's commitment to the framework and their extant platforms. It seems like Microsoft has a bad habit of coming up with something new, hyping it for a few years, and then relegating it to the waste-bin essentially abandoning the developers who chose it. First it was MFC and VB6, then Windows Forms, and now there's WPF. Also with .NET, versions of Windows were progressively nicked off the support list. Looks like WPF could be here to stay for a while, but since its not open source its really in Microsoft's hands. I'm also concerned about the overhead and performance of WPF since some of our applications involve processing large amounts of information and doing real-time data capture. Qt seems like a really good option, but it doesn't have all the features of WPF/.NET couldn't use languages like C#. Basically, what does the community think about Microsoft's commitment to WPF compared with previous frameworks? Are the performance considerations significant enough to avoid using it for a realtime app? And, how significant are the benefits of WPF/.NET in terms of productivity and features compared to Qt?

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  • Delphi Exception handling problem with multiple Exception handling blocks

    - by Robert Oschler
    I'm using Delphi Pro 6 on Windows XP with FastMM 4.92 and the JEDI JVCL 3.0. Given the code below, I'm having the following problem: only the first exception handling block gets a valid instance of E. The other blocks match properly with the class of the Exception being raised, but E is unassigned (nil). For example, given the current order of the exception handling blocks when I raise an E1 the block for E1 matches and E is a valid object instance. However, if I try to raise an E2, that block does match, but E is unassigned (nil). If I move the E2 catching block to the top of the ordering and raise an E1, then when the E1 block matches E is is now unassigned. With this new ordering if I raise an E2, E is properly assigned when it wasn't when the E2 block was not the first block in the ordering. Note I tried this case with a bare-bones project consisting of just a single Delphi form. Am I doing something really silly here or is something really wrong? Thanks, Robert type E1 = class(EAbort) end; E2 = class(EAbort) end; procedure TForm1.Button1Click(Sender: TObject); begin try raise E1.Create('hello'); except On E: E1 do begin OutputDebugString('E1'); end; On E: E2 do begin OutputDebugString('E2'); end; On E: Exception do begin OutputDebugString('E(all)'); end; end; // try() end;

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