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• Formal Languages, Inductive Proofs &amp; Regular Expressions

  - by MarkPearl

  So I am slogging away at my UNISA stuff. I have just finished doing the initial once non stop read through the first 11 chapters of my COS 201 Textbook - “Introduction to Computer Theory 2nd Edition” by Daniel Cohen. It has been an interesting couple of days, with familiar concepts coming up as well as some new territory. In this posting I am going to cover the first couple of chapters of the book. Let start with Formal Languages… What exactly is a formal language? Pretty much a no duh question for me but still a good one to ask – a formal language is a language that is defined in a precise mathematical way. Does that mean that the English language is a formal language? I would say no – and my main motivation for this is that one can have an English sentence that is correct grammatically that is also ambiguous. For example the ambiguous sentence: "I once shot an elephant in my pyjamas.” For this and possibly many other reasons that I am unaware of, English is termed a “Natural Language”. So why the importance of formal languages in computer science? Again a no duh question in my mind… If we want computers to be effective and useful tools then we need them to be able to evaluate a series of commands in some form of language that when interpreted by the device no confusion will exist as to what we were requesting. Imagine the mayhem that would exist if a computer misinterpreted a command to print a document and instead decided to delete it. So what is a Formal Language made up of… For my study purposes a language is made up of a finite alphabet. For a formal language to exist there needs to be a specification on the language that will describe whether a string of characters has membership in the language or not. There are two basic ways to do this: By a “machine” that will recognize strings of the language (e.g. Finite Automata). By a rule that describes how strings of a language can be formed (e.g. Regular Expressions). When we use the phrase “string of characters”, we can also be referring to a “word”. What is an Inductive Proof? So I am not to far into my textbook and of course it starts referring to proofs and different types. I have had to go through several different approaches of proofs in the past, but I can never remember their formal names , so when I saw “inductive proof” I thought to myself – what the heck is that? Google to the rescue… An inductive proof is like a normal proof but it employs a neat trick which allows you to prove a statement about an arbitrary number n by first proving it is true when n is 1 and then assuming it is true for n=k and showing it is true for n=k+1. The idea is that if you want to show that someone can climb to the nth floor of a fire escape, you need only show that you can climb the ladder up to the fire escape (n=1) and then show that you know how to climb the stairs from any level of the fire escape (n=k) to the next level (n=k+1). Does this sound like a form of recursion? No surprise then that in the same chapter they deal with recursive definitions. An example of a recursive definition for the language EVEN would the 3 rules below: 2 is in EVEN If x is in EVEN then so is x+2 The only elements in the set EVEN are those that be produced by the rules above. Nothing to exciting… So if a definition for a language is done recursively, then it makes sense that the language can be proved using induction. Regular Expressions So I am wondering to myself what use is this all – in fact – I find this the biggest challenge to any university material is that it is quite hard to find the immediate practical applications of some theory in real life stuff. How great was my joy when I suddenly saw the word regular expression being introduced. I had been introduced to regular expressions on Stack Overflow where I was trying to recognize if some text measurement put in by a user was in a valid form or not. For instance, the imperial system of measurement where you have feet and inches can be represented in so many different ways. I had eventually turned to regular expressions as an easy way to check if my parser could correctly parse the text or not and convert it to a normalize measurement. So some rules about languages and regular expressions… Any finite language can be represented by at least one if not more regular expressions A regular expressions is almost a rule syntax for expressing how regular languages can be formed regular expressions are cool For a regular expression to be valid for a language it must be able to generate all the words in the language and no other words. This is important. It doesn’t help me if my regular expression parses 100% of my measurement texts but also lets one or two invalid texts to pass as well. Okay, so this posting jumps around a bit – but introduces some very basic fundamentals for the subject which will be built on in later postings… Time to go and do some practical examples now…

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• Visualising data a different way with Pivot collections

  - by Rob Farley

  Roger’s been doing a great job extending PivotViewer recently, and you can find the list of LobsterPot pivots at http://pivot.lobsterpot.com.au Many months back, the TED Talk that Gary Flake did about Pivot caught my imagination, and I did some research into it. At the time, most of what we did with Pivot was geared towards what we could do for clients, including making Pivot collections based on students at a school, and using it to browse PDF invoices by their various properties. We had actual commercial work based on Pivot collections back then, and it was all kinds of fun. Later, we made some collections for events that were happening, and even got featured in the TechEd Australia keynote. But I’m getting ahead of myself... let me explain the concept. A Pivot collection is an XML file (with .cxml extension) which lists Items, each linking to an image that’s stored in a Deep Zoom format (this means that it contains tiles like Bing Maps, so that the browser can request only the ones of interest according to the zoom level). This collection can be shown in a Silverlight application that uses the PivotViewer control, or in the Pivot Browser that’s available from getpivot.com. Filtering and sorting the items according to their facets (attributes, such as size, age, category, etc), the PivotViewer rearranges the way that these are shown in a very dynamic way. To quote Gary Flake, this lets us “see patterns which are otherwise hidden”. This browsing mechanism is very suited to a number of different methods, because it’s just that – browsing. It’s not searching, it’s more akin to window-shopping than doing an internet search. When we decided to put something together for the conferences such as TechEd Australia 2010 and the PASS Summit 2010, we did some screen-scraping to provide a different view of data that was already available online. Nick Hodge and Michael Kordahi from Microsoft liked the idea a lot, and after a bit of tweaking, we produced one that Michael used in the TechEd Australia keynote to show the variety of talks on offer. It’s interesting to see a pattern in this data: The Office track has the most sessions, but if the Interactive Sessions and Instructor-Led Labs are removed, it drops down to only the sixth most popular track, with Cloud Computing taking over. This is something which just isn’t obvious when you look an ordinary search tool. You get a much better feel for the data when moving around it like this. The more observant amongst you will have noticed some difference in the collection that Michael is demonstrating in the picture above with the screenshots I’ve shown. That’s because it’s been extended some more. At the SQLBits conference in the UK this year, I had some interesting discussions with the guys from Xpert360, particularly Phil Carter, who I’d met in 2009 at an earlier SQLBits conference. They had got around to producing a Pivot collection based on the SQLBits data, which we had been planning to do but ran out of time. We discussed some of ways that Pivot could be used, including the ways that my old friend Howard Dierking had extended it for the MSDN Magazine. I’m not suggesting I influenced Xpert360 at all, but they certainly inspired us with some of their posts on the matter So with LobsterPot guys David Gardiner and Roger Noble both having dabbled in Pivot collections (and Dave doing some for clients), I set Roger to work on extending it some more. He’s used various events and so on to be able to make an environment that allows us to do quick deployment of new collections, as well as showing the data in a grid view which behaves as if it were simply a third view of the data (the other two being the array of images and the ‘histogram’ view). I see PivotViewer as being a significant step in data visualisation – so much so that I feature it when I deliver talks on Spatial Data Visualisation methods. Any time when there is information that can be conveyed through an image, you have to ask yourself how best to show that image, and whether that image is the focal point. For Spatial data, the image is most often a map, and the map becomes the central mode for navigation. I show Pivot with postcode areas, since I can browse the postcodes based on their data, and many of the images are recognisable (to locals of South Australia). Naturally, the images could link through to the map itself, and so on, but generally people think of Spatial data in terms of navigating a map, which doesn’t always gel with the information you’re trying to extract. Roger’s even looking into ways to hook PivotViewer into the Bing Maps API, in a similar way to the Deep Earth project, displaying different levels of map detail according to how ‘zoomed in’ the images are. Some of the work that Dave did with one of the schools was generating the Deep Zoom tiles “on the fly”, based on images stored in a database, and Roger has produced a collection which uses images from flickr, that lets you move from one search term to another. Pulling the images down from flickr.com isn’t particularly ideal from a performance aspect, and flickr doesn’t store images in a small-enough format to really lend itself to this use, but you might agree that it’s an interesting concept which compares nicely to using Maps. I’m looking forward to future versions of the PivotViewer control, and hope they provide many more events that can be used, and even more hooks into it. Naturally, LobsterPot could help provide your business with a PivotViewer experience, but you can probably do a lot of it yourself too. There’s a thorough guide at getpivot.com, which is how we got into it. For some examples of what we’ve done, have a look at http://pivot.lobsterpot.com.au. I’d like to see PivotViewer really catch on a data visualisation tool.

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• Upcoming EMEA, APAC & US Events with MySQL in 2014

  - by Lenka Kasparova

  As an update to the previous announcement from Mar 25, 2014 please find below the updated list of events where MySQL Community team is attending and/or supporting. This time you can find not only EMEA & APAC ones but also conferences & events we are covering in the US & Canada. You are invited to meet our engineers at the events below.   EMEA  NEW!! BGOUG, Sandanski, Bulgaria, June 13, 2014  Georgi Kodinov will attend and speak at this local Oracle User Group event. Feel free to come. PHP Tour Lyon, Lyon, France, June 23-24, 2014 MySQL team is going to be part of this show as well, we are not going to have a booth here but very active networking by our french MySQL team around the event. Come to meet us and talk to us! NEW!! Converge Conference, Glasgow, Scotland, August 15-16, 2014  MySQL Community Manager, David Stokes attends with MySQL talk. NEW!! CakeFest, Madrid, Spain, August 21-24, 2014  A talk on "Scaling Your MySQL instances AND keeping your Sanity" will be given by the MySQL Community Manager, David Stokes. Froscon 2014, St.Augustin, Germany, August 23-24, 2014 Please visit our booth as well as watch the Froscon website for the schedule updates. NEW!! SymfonyLive, UK, London, September 25-26, 2014 MySQL Community Magers, David Stokes & Morgan Tocker submitted MySQL talks for this show. Schedule will be announced later on. DrupalCon Amsterdam, The Netherlands, September 29-Oct 3, 2014 Meet us at our booth at DrupalCon Amsterdam. For the schedule please watch the DrupalCon website. All Your Base, Oxford UK, October 17, 2014  Come to visit our MySQL booth and talk to our MySQL experts. NEW!! WebTechCon / IPC, Munich Germany, October 26-29, 2014 NEW!! DOAG, Nuremberg, Germany, November 18-20, 2014 There will be a full day of MySQL talks and one full day of MySQL workshop & sessions with live demo. This event is simply hard to miss! NEW!! Forum PHP Paris, France, November 21-22, 2014 More details: TBD NEW!! UK OUG, Liverpool, UK, December 8-10, 2014 MySQL will be part of the Oracle booth and we hope to get more space for MySQL talks.  USA NEW!! Texas Linux Fest, Austin, Texas, US, June 13-14, 2014 NEW!! SouthEast Linux Fest, Charlotte, US, June 20-22, 2014 NEW!! Debian Conference 2014, Portland, OR, US, August 23-31, 2014 NEW!! FossetCon, Orlando, US, September 11-13, 2014 NEW!! Oracle Open World, San Francisco, US, September 29-October 3, 2014 NEW!! MySQL Central @ Open/World, San Francisco, US, September 29-October 3, 2014 NEW!! PyTexas 2014, Dallas, TX, US, October 3-5, 2014 NEW!! All Things Open (replacing POSSCON), Raleigh, NC, October 23-24, 2014 NEW!! Ohio LinuxFest 2014, Columbus, Ohio, US, October 24-25, 2014 NEW!! ZendCon PHP, Santa Clara, US, October 27-30, 2014 NEW!! Kuali Days 2014, Indianapolis, US, November 10-13, 2014 NEW!! Live 360, Orlando, FL, US, November 17-20, 2014 APAC OpenSourceConference Japan, Hokkaido, June 13-14, 2014 MySQL is represented by Ryusuke Kajiyama with the talk on "MySQL Technology Updates". NEW!! db tech showcase, Osaka Japan, June 18-20, 2014 Three MySQL talks are scheduled for this show, "MySQL for Oracle DBA" & "MySQL Technology Updates" by Ryusuke Kajiyama. The last talk will be on MySQL Fabric by Yoshiaki Yamasaki. NEW!! PyCon Singapore, Singapore, June 18-20, 2014 Ryusuke Kajiyama will be talking about "Sharding and scale-out using Python-based MySQL Fabric". NEW!! COSCUP, Taipei, Taiwan, July 19-20, 2014 We are going to run a technical session on MySQL Workbench & one talk on how to make MySQL better MySQL. NEW!! PyCon New Zealand, Wellington, New Zealand, September 13-14, 2014 MySQL talks were submitted as well as one talk by Solaris Modernization team on Python & Solaris, watch the website for schedule updates. NEW!! PyCon Japan, Tokyo Japan, September 13-15, 2014 MySQL will be a MySQL session speaker, no schedule is announced yet. Ruby Kaigi, Tokyo, Japan, September 18-20, 2014 Another event MySQL supports and attends in APAC region. Ruby Kaigi is the international Ruby Conference in Japan, Tokyo. Ruby started in Japan, so Ruby Kaigi has excellent speakers and developers! MySQL team is going to be present at this conference with MySQL talks and active networking around the venue. NEW!! PyCon India, Bangalore, India, September 26-28, 2014 A MySQL talk on "MySQL Utilities scaling MySQL with Python" has been submitted, please watch the PyCon website for the schedule updates. NEW!! OpenSourceConference Japan, Tokyo, October 18-19, 2014 NEW!! OpenSource India, Bengaluru, India, November 7-8, 2014 NEW!! OpenSourceConference Japan, Fukuoka, November 14-15, 2014 You can check the MySQL wikis for updates on the conferences we are attending. Next time I hope to have more details for each event above (especially for the US ones).

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• Task-It Webinar - Source Code

  Last week I presented a webinar called "Building a real-world application with RadControls for Silverlight 4". For those that didn't get to see the webinar, you can view it here: Building a read-world application with RadControls for Silverlight 4 Since the webinar I've received several requests asking if I could post the source code for the simple application I showed demonstrating some of the techniques used in the development of Task-It, such as MVVM, Commands and Internationalization. This source code is now available for downloadhere. After downloading the source: Extract it to the location of your choice on your hard-drive Open the solution Right-click ModuleProject.Web and selecte 'Set as StartUp Project'. Right-click ProjectTestPage.aspx and selected 'Set as Start Page' Create a database in SQL Server called WebinarProject. Navigate to the Database folder under the WebinarProject directory and run the .sql script against your WebinarProject database. The last two steps are necessary only for the Tasks page to work properly (using WCF RIA Services). Now some notes about each page: Code-behind This is not the way I recommend coding a line-of-business application in Silverlight, but simply wanted to show how the code-behind approach would look. Command This page introduces MVVM and Commands. You'll notice in the XAML that the Command property of theRadMenuItem and the Button are both bound to a SaveCommand. That comes from the view model. If you look in the code- behind of the user control you'll see that an instance of a CommandViewModel is instantiated and set as the DataContext of the UserControl.There is also a listener for the view model's SaveCompleted event. When this is fired, it tells the view (UserControl) to display the MessageBox. Internationalization This sample is similar to the previous one, but instead of using hard-coded strings in the UI, the strings are obtained via binding toview model properties. The view model gets the strings from the .resx files (Strings.resx or Strings.de.resx) under Assets/Resources. If you uncomment the call to ShowGerman() in App.xaml.cs's Application_Startup method and re-run the application, you will see the UI in German. Note that this code, which sets the CurrentCulture and CurrentUICulture on the current thread to "de" (German) is for testing purposes only. RadWindow Once again, very similar to the previous example.The difference is that we are now using a RadWindow to display the 'Saved' message instead of a MessageBox. The advantage here is that we do not have to hold on to a reference to the view model in our code behind so that we can get the 'Saved' message from it. The RadWindow's DataContext is now also bound to the view model, so within its XAML we can bind directly to properties in the view model. Much nicer, and cleaner. One other thing I introduced in this example is the use of spacer Rectangles. Rather than setting a width and/or height on the rectangles for spacing, I am now referencing a style in my ResourceDictionary called StandardSpacerStyle. I like doing this better than using margins or padding because now I have a reusable way to create space between elements, the Rectangle does not show (because I have not set its Fill color), and I can change my spacing throughout the user interface in one place if I'd like. Tasks This page is quite a bit different than the other four. It is a very simple, stripped-down version of the Tasks page in the Task-It application. The Tasks.xaml UserControl has a ContentControl, and the Content of that control is set based on whether we are looking at the list of tasks or editing a task. So it displays one of two child UserControls, which are called List and Details. List has the RadGridView, Details has the form. In the code-behind of the Tasks UserControl I am once again setting its DataContext to a view model class. The nice thing is, whichever child UserControl is being displayed (List or Details) inherits its DataContext from its parent control (Tasks), so I do not have to explicitly set it. The List UserControl simply displays a RadGridView whose ItemsSource is bound to a property in the view model called Tasks, and its SelectedItem property is bound to a property in the view model called SelectedItem. The SelectedItem binding must be TwoWay so that the view is notified when the SelectedItem changes in the view model, and the view model is notified when something changes in the view (like when a user changes the Name and/or DueDate in the form). You'll also notice that the form's TextBox and RadDatePicker are also TwoWay bound to the SelectedItem property in the view model. You can experiment with the binding by removing TwoWay and see how changes in the form do not show up in the RadGridView. So here we have an example of two different views (List and Details) that are both bound to the same view model...and actually, so is the Tasks UserControl, so it is really three views. WCF RIA Services By the way, I am using WCF RIA Services to retrieve data for the RadGridView and save the data when the user clicks the Save button in the form. I created a really simple ADO.NET Entity Data Model in WebinarProject.Web called DataModel.edmx. I also created a simple Domain Data Service called DataService that has methods for retrieving data, inserting, updating and deleting. However I am only using the retrieval and update methods in this sample. Note that I do not currently have any validation in place on the form, as I wanted to keep the sample as simple as possible. Wrap up Technically, I should move the calls to WCF RIA Services out of the view model and put them into a separate layer, but this works for now, and that is a topic for another day! Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Advanced donut caching: using dynamically loaded controls

  - by DigiMortal

  Yesterday I solved one caching problem with local community portal. I enabled output cache on SharePoint Server 2007 to make site faster. Although caching works fine I needed to do some additional work because there are some controls that show different content to different users. In this example I will show you how to use “donut caching” with user controls – powerful way to drive some content around cache. About donut caching Donut caching means that although you are caching your content you have some holes in it so you can still affect the output that goes to user. By example you can cache front page on your site and still show welcome message that contains correct user name. To get better idea about donut caching I suggest you to read ScottGu posting Tip/Trick: Implement "Donut Caching" with the ASP.NET 2.0 Output Cache Substitution Feature. Basically donut caching uses ASP.NET substitution control. In output this control is replaced by string you return from static method bound to substitution control. Again, take a look at ScottGu blog posting I referred above. Problem If you look at Scott’s example it is pretty plain and easy by its output. All it does is it writes out current user name as string. Here are examples of my login area for anonymous and authenticated users:    It is clear that outputting mark-up for these views as string is pretty lame to implement in code at string level. Every little change in design will end up with new version of controls library because some parts of design “live” there. Solution: using user controls I worked out easy solution to my problem. I used cache substitution and user controls together. I have three user controls: LogInControl – this is the proxy control that checks which “real” control to load. AnonymousLogInControl – template and logic for anonymous users login area. AuthenticatedLogInControl – template and logic for authenticated users login area. This is the control we render for each user separately because it contains user name and user profile fill percent. Anonymous control is not very interesting because it is only about keeping mark-up in separate file. Interesting parts are LogInControl and AuthenticatedLogInControl. Creating proxy control The first thing was to create control that has substitution area where “real” control is loaded. This proxy control should also be available to decide which control to load. The definition of control is very primitive. <%@ Control EnableViewState="false" Inherits="MyPortal.Profiles.LogInControl" %> <asp:Substitution runat="server" MethodName="ShowLogInBox" /> But code is a little bit tricky. Based on current user instance we decide which login control to load. Then we create page instance and load our control through it. When control is loaded we will call DataBind() method. In this method we evaluate all fields in loaded control (it was best choice as Load and other events will not be fired). Take a look at the code. public static string ShowLogInBox(HttpContext context) {     var user = SPContext.Current.Web.CurrentUser;     string controlName;       if (user != null)         controlName = "AuthenticatedLogInControl.ascx";     else         controlName = "AnonymousLogInControl.ascx";       var path = "~/_controltemplates/" + controlName;     var output = new StringBuilder(10000);       using(var page = new Page())     using(var ctl = page.LoadControl(path))     using(var writer = new StringWriter(output))     using(var htmlWriter = new HtmlTextWriter(writer))     {         ctl.DataBind();         ctl.RenderControl(htmlWriter);     }     return output.ToString(); } When control is bound to data we ask to render it its contents to StringBuilder. Now we have the output of control as string and we can return it from our method. Of course, notice how correct I am with resources disposing. :) The method that returns contents for substitution control is static method that has no connection with control instance because hen page is read from cache there are no instances of controls available. Conclusion As you saw it was not very hard to use donut caching with user controls. Instead of writing mark-up of controls to static method that is bound to substitution control we can still use our user controls.

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• Superpower Your Touchpad Computer with Scrybe

  - by Matthew Guay

  Are you looking for a way to help your Touchpad computer make you more productive?  Here’s a quick look at Scrybe, a new application from Synaptics that lets you superpower it. Touchpad devices have become increasingly more interesting as they’ve included support for multi-touch gestures.  Scrybe takes it to the next level and lets you use your touchpad as an application launcher.  You can launch any application, website, or complete many common commands on your computer with a simple gesture.  Scrybe works with most modern Synaptics touchpads, which are standard on most laptops and netbooks.  It is optimized for newer multi-touch touchpads, but can also work with standard single-touch touchpads.  It works on Windows 7, Vista, and XP, so chances are it will work with your laptop or netbook. Get Started With Scrybe Head over to the Scrybe website and download the latest version (link below).  You are asked to enter your email address, name, and information about your computer…but you actually only have to enter your email address.  Click Download when finished. Run the installer when it’s download.  It will automatically download the latest Synaptics driver for your touchpad and any other components needed for Scrybe.  Note that the Scrybe installer will ask to install the Yahoo! toolbar, so uncheck this to avoid adding this worthless browser toolbar. Using Scrybe To open an application or website with a gesture, press 3 fingers on your touchpad at once, or if your touchpad doesn’t support multi-touch gestures, then press Ctrl+Alt and press 1 finger on your touchpad.  This will open the Scrype input pane; start drawing a gesture, and you’ll see it on the grey square.  The input pane shows some default gestures you can try. Here we drew an “M”, which opens our default Music player.  As soon as you finish the gesture and lift up your finger, Scrybe will open the application or website you selected. A notification balloon will let you know what gesture was preformed. When you’re entering your gesture, the input pane will show white “ink”.  The “ink” will turn blue if the command is recognized, but will turn red if it isn’t.  If Scrybe doesn’t recognize your command, press 3 fingers and try again. Scrybe Control Panel You can open the Scrybe Control panel to enter or change commands by entering a box-like gesture, or right-clicking the Scrybe icon in your system tray and selecting “Scrybe Control Panel”. Scrybe has many pre-configured gestures that you can preview and even practice. All of the gestures in the Popular tab are preset and cannot be changed.  However, the ones in the favorites tab can be edited.  Select the gesture you wish to edit, and click the gear icon to change it.  Here we changed the email gesture to open Hotmail instead of the default Yahoo Mail. Scrybe can also help you perform many common Windows commands such as Copy and Undo.  Select the Tools tab to see all of these commands.   Scrybe has many settings you may wish to change.  Select the Preferences button in the Control Panel to change these.  Here’s some of the settings we changed. Uncheck “Display a message” to turn off the tooltip notifications when you enter a gesture Uncheck “Show symbol hints” to turn off the sidebar on the input pane Select the search engine you want to open with the Search Gesture.  The default is Yahoo, but you can choose your favorite. Adding a new Scrybe Gesture The default Scrybe options are useful, but the best part is that you can assign gestures to your own programs or websites.  Open the Scrybe control panel, and click the plus sign on the bottom left corner.  Enter a name for your gesture, and then choose if it is for a website or an application. If you want the gesture to open a website, enter the address in the box. Alternately, if you want your gesture to open an application, select Launch Application and then either enter the path to the application, or click the button beside the Launch field and browse to it. Now click the down arrow on the blue box and choose one of the gestures for your application or website. Your new gesture will show up under the Favorites tab in the Scrybe control panel, and you can use it whenever you want from Scrybe, or practice the gesture by selecting the Practice button. Conclusion If you enjoy multi-touch gestures, you may find Scrybe very useful on your laptop or netbook.  Scrybe recognizes gestures fairly easily, even if you don’t enter them perfectly correctly.  Just like pinch-to-zoom and two-finger scroll, Scrybe can quickly become something you miss on other laptops. Download Scrybe (registration required) Similar Articles Productive Geek Tips Fixing Firefox Scrolling Problems with Dell Synaptics TouchpadRemove Synaptics Touchpad Icon from System TrayRoll Back Troublesome Device Drivers in Windows VistaChange Your Computer Name in Windows 7 or VistaLet Somebody Use Your Computer Without Logging Off in Ubuntu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Fun with 47 charts and graphs Tomorrow is Mother’s Day Check the Average Speed of YouTube Videos You’ve Watched OutlookStatView Scans and Displays General Usage Statistics How to Add Exceptions to the Windows Firewall Office 2010 reviewed in depth by Ed Bott

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• Visual Studio Load Testing using Windows Azure

  - by Tarun Arora

  In my opinion the biggest adoption barrier in performance testing on smaller projects is not the tooling but the high infrastructure and administration cost that comes with this phase of testing. Only if a reusable solution was possible and infrastructure management wasn’t as expensive, adoption would certainly spike. It certainly is possible if you bring Visual Studio and Windows Azure into the equation. It is possible to run your test rig in the cloud without getting tangled in SCVMM or Lab Management. All you need is an active Azure subscription, Windows Azure endpoint enabled developer workstation running visual studio ultimate on premise, windows azure endpoint enabled worker roles on azure compute instances set up to run as test controllers and test agents. My test rig is running SQL server 2012 and Visual Studio 2012 RC agents. The beauty is that the solution is reusable, you can open the azure project, change the subscription and certificate, click publish and *BOOM* in less than 15 minutes you could have your own test rig running in the cloud. In this blog post I intend to show you how you can use the power of Windows Azure to effectively abstract the administration cost of infrastructure management and lower the total cost of Load & Performance Testing. As a bonus, I will share a reusable solution that you can use to automate test rig creation for both VS 2010 agents as well as VS 2012 agents. Introduction The slide show below should help you under the high level details of what we are trying to achive... Leveraging Azure for Performance Testing View more PowerPoint from Avanade Scenario 1 – Running a Test Rig in Windows Azure To start off with the basics, in the first scenario I plan to discuss how to, - Automate deployment & configuration of Windows Azure Worker Roles for Test Controller and Test Agent - Automate deployment & configuration of SQL database on Test Controller on the Test Controller Worker Role - Scaling Test Agents on demand - Creating a Web Performance Test and a simple Load Test - Managing Test Controllers right from Visual Studio on Premise Developer Workstation - Viewing results of the Load Test - Cleaning up - Have the above work in the shape of a reusable solution for both VS2010 and VS2012 Test Rig Scenario 2 – The scaled out Test Rig and sharing data using SQL Azure A scaled out version of this implementation would involve running multiple test rigs running in the cloud, in this scenario I will show you how to sync the load test database from these distributed test rigs into one SQL Azure database using Azure sync. The selling point for this scenario is being able to collate the load test efforts from across the organization into one data store. - Deploy multiple test rigs using the reusable solution from scenario 1 - Set up and configure Windows Azure Sync - Test SQL Azure Load Test result database created as a result of Windows Azure Sync - Cleaning up - Have the above work in the shape of a reusable solution for both VS2010 and VS2012 Test Rig The Ingredients Though with an active MSDN ultimate subscription you would already have access to everything and more, you will essentially need the below to try out the scenarios, 1. Windows Azure Subscription 2. Windows Azure Storage – Blob Storage 3. Windows Azure Compute – Worker Role 4. SQL Azure Database 5. SQL Data Sync 6. Windows Azure Connect – End points 7. SQL 2012 Express or SQL 2008 R2 Express 8. Visual Studio All Agents 2012 or Visual Studio All Agents 2010 9. A developer workstation set up with Visual Studio 2012 – Ultimate or Visual Studio 2010 – Ultimate 10. Visual Studio Load Test Unlimited Virtual User Pack. Walkthrough To set up the test rig in the cloud, the test controller, test agent and SQL express installers need to be available when the worker role set up starts, the easiest and most efficient way is to pre upload the required software into Windows Azure Blob storage. SQL express, test controller and test agent expose various switches which we can take advantage of including the quiet install switch. Once all the 3 have been installed the test controller needs to be registered with the test agents and the SQL database needs to be associated to the test controller. By enabling Windows Azure connect on the machines in the cloud and the developer workstation on premise we successfully create a virtual network amongst the machines enabling 2 way communication. All of the above can be done programmatically, let’s see step by step how… Scenario 1 Video Walkthrough–Leveraging Windows Azure for performance Testing Scenario 2 Work in progress, watch this space for more… Solution If you are still reading and are interested in the solution, drop me an email with your windows live id. I’ll add you to my TFS preview project which has a re-usable solution for both VS 2010 and VS 2012 test rigs as well as guidance and demo performance tests.   Conclusion Other posts and resources available here. Possibilities…. Endless!

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• Kendo UI Mobile with Knockout for Master-Detail Views

  - by Steve Michelotti

  Lately I’ve been playing with Kendo UI Mobile to build iPhone apps. It’s similar to jQuery Mobile in that they are both HTML5/JavaScript based frameworks for buildings mobile apps. The primary thing that drew me to investigate Kendo UI was its innate ability to adaptively render a native looking app based on detecting the device it’s currently running on. In other words, it will render to look like a native iPhone app if it’s running on an iPhone and it will render to look like a native Droid app if it’s running on a Droid. This is in contrast to jQuery Mobile which looks the same on all devices and, therefore, it can never quite look native for whatever device it’s running on. My first impressions of Kendo UI were great. Using HTML5 data-* attributes to define “roles” for UI elements is easy, the rendering looked great, and the basic navigation was simple and intuitive. However, I ran into major confusion when trying to figure out how to “correctly” build master-detail views. Since I was already very family with KnockoutJS, I set out to use that framework in conjunction with Kendo UI Mobile to build the following simple scenario: I wanted to have a simple “Task Manager” application where my first screen just showed a list of tasks like this:   Then clicking on a specific task would navigate to a detail screen that would show all details of the specific task that was selected:   Basic navigation between views in Kendo UI is simple. The href of an <a> tag just needs to specify a hash tag followed by the ID of the view to navigate to as shown in this jsFiddle (notice the href of the <a> tag matches the id of the second view):   Direct link to jsFiddle: here. That is all well and good but the problem I encountered was: how to pass data between the views? Specifically, I need the detail view to display all the details of whichever task was selected. If I was doing this with my typical technique with KnockoutJS, I know exactly what I would do. First I would create a view model that had my collection of tasks and a property for the currently selected task like this: 1: function ViewModel() { 2: var self = this; 3: self.tasks = ko.observableArray(data); 4: self.selectedTask = ko.observable(null); 5: } Then I would bind my list of tasks to the unordered list - I would attach a “click” handler to each item (each <li> in the unordered list) so that it would select the “selectedTask” for the view model. The problem I found is this approach simply wouldn’t work for Kendo UI Mobile. It completely ignored the click handlers that I was trying to attach to the <a> tags – it just wanted to look at the href (at least that’s what I observed). But if I can’t intercept this, then *how* can I pass data or any context to the next view? The only thing I was able to find in the Kendo documentation is that you can pass query string arguments on the view name you’re specifying in the href. This enabled me to do the following: Specify the task ID in each href – something like this: <a href=”#taskDetail?id=3></a> Attach an “init method” (via the “data-show” attribute on the details view) that runs whenever the view is activated Inside this “init method”, grab the task ID passed from the query string to look up the item from my view model’s list of tasks in order to set the selected task I was able to get all that working with about 20 lines of JavaScript as shown in this jsFiddle. If you click on the Results tab, you can navigate between views and see the the detail screen is correctly binding to the selected item:   Direct link to jsFiddle: here.   With all that being done, I was very happy to get it working with the behavior I wanted. However, I have no idea if that is the “correct” way to do it or if there is a “better” way to do it. I know that Kendo UI comes with its own data binding framework but my preference is to be able to use (the well-documented) KnockoutJS since I’m already familiar with that framework rather than having to learn yet another new framework. While I think my solution above is probably “acceptable”, there are still a couple of things that bug me about it. First, it seems odd that I have to loop through my items to *find* my selected item based on the ID that was passed on the query string - normally, with Knockout I can just refer directly to my selected item from where it was used. Second, it didn’t feel exactly right that I had to rely on the “data-show” method of the details view to set my context – normally with Knockout, I could just attach a click handler to the <a> tag that was actually clicked by the user in order to set the “selected item.” I’m not sure if I’m being too picky. I know there are many people that have *way* more expertise in Kendo UI compared to me – I’d be curious to know if there are better ways to achieve the same results.

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• Diving into OpenStack Network Architecture - Part 2 - Basic Use Cases

  - by Ronen Kofman

    rkofman Normal rkofman 4 138 2014-06-05T03:38:00Z 2014-06-05T05:04:00Z 3 2735 15596 Oracle Corporation 129 36 18295 12.00 Clean Clean false false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} In the previous post we reviewed several network components including Open vSwitch, Network Namespaces, Linux Bridges and veth pairs. In this post we will take three simple use cases and see how those basic components come together to create a complete SDN solution in OpenStack. With those three use cases we will review almost the entire network setup and see how all the pieces work together. The use cases we will use are: 1.       Create network – what happens when we create network and how can we create multiple isolated networks 2.       Launch a VM – once we have networks we can launch VMs and connect them to networks. 3.       DHCP request from a VM – OpenStack can automatically assign IP addresses to VMs. This is done through local DHCP service controlled by OpenStack Neutron. We will see how this service runs and how does a DHCP request and response look like. In this post we will show connectivity, we will see how packets get from point A to point B. We first focus on how a configured deployment looks like and only later we will discuss how and when the configuration is created. Personally I found it very valuable to see the actual interfaces and how they connect to each other through examples and hands on experiments. After the end game is clear and we know how the connectivity works, in a later post, we will take a step back and explain how Neutron configures the components to be able to provide such connectivity.  We are going to get pretty technical shortly and I recommend trying these examples on your own deployment or using the Oracle OpenStack Tech Preview. Understanding these three use cases thoroughly and how to look at them will be very helpful when trying to debug a deployment in case something does not work. Use case #1: Create Network Create network is a simple operation it can be performed from the GUI or command line. When we create a network in OpenStack the network is only available to the tenant who created it or it could be defined as “shared” and then it can be used by all tenants. A network can have multiple subnets but for this demonstration purpose and for simplicity we will assume that each network has exactly one subnet. Creating a network from the command line will look like this: # neutron net-create net1 Created a new network: +---------------------------+--------------------------------------+ | Field                     | Value                                | +---------------------------+--------------------------------------+ | admin_state_up            | True                                 | | id                        | 5f833617-6179-4797-b7c0-7d420d84040c | | name                      | net1                                 | | provider:network_type     | vlan                                 | | provider:physical_network | default                              | | provider:segmentation_id  | 1000                                 | | shared                    | False                                | | status                    | ACTIVE                               | | subnets                   |                                      | | tenant_id                 | 9796e5145ee546508939cd49ad59d51f     | +---------------------------+--------------------------------------+ Creating a subnet for this network will look like this: # neutron subnet-create net1 10.10.10.0/24 Created a new subnet: +------------------+------------------------------------------------+ | Field            | Value                                          | +------------------+------------------------------------------------+ | allocation_pools | {"start": "10.10.10.2", "end": "10.10.10.254"} | | cidr             | 10.10.10.0/24                                  | | dns_nameservers  |                                                | | enable_dhcp      | True                                           | | gateway_ip       | 10.10.10.1                                     | | host_routes      |                                                | | id               | 2d7a0a58-0674-439a-ad23-d6471aaae9bc           | | ip_version       | 4                                              | | name             |                                                | | network_id       | 5f833617-6179-4797-b7c0-7d420d84040c           | | tenant_id        | 9796e5145ee546508939cd49ad59d51f               | +------------------+------------------------------------------------+ We now have a network and a subnet, on the network topology view this looks like this: Now let’s dive in and see what happened under the hood. Looking at the control node we will discover that a new namespace was created: # ip netns list qdhcp-5f833617-6179-4797-b7c0-7d420d84040c   The name of the namespace is qdhcp-<network id> (see above), let’s look into the namespace and see what’s in it: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo     inet6 ::1/128 scope host        valid_lft forever preferred_lft forever 12: tap26c9b807-7c: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN     link/ether fa:16:3e:1d:5c:81 brd ff:ff:ff:ff:ff:ff     inet 10.10.10.3/24 brd 10.10.10.255 scope global tap26c9b807-7c     inet6 fe80::f816:3eff:fe1d:5c81/64 scope link        valid_lft forever preferred_lft forever   We see two interfaces in the namespace, one is the loopback and the other one is an interface called “tap26c9b807-7c”. This interface has the IP address of 10.10.10.3 and it will also serve dhcp requests in a way we will see later. Let’s trace the connectivity of the “tap26c9b807-7c” interface from the namespace.  First stop is OVS, we see that the interface connects to bridge  “br-int” on OVS: # ovs-vsctl show 8a069c7c-ea05-4375-93e2-b9fc9e4b3ca1     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-ex         Port br-ex             Interface br-ex                 type: internal     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port "tap26c9b807-7c"             tag: 1             Interface "tap26c9b807-7c"                 type: internal         Port br-int             Interface br-int                 type: internal     ovs_version: "1.11.0"   In the picture above we have a veth pair which has two ends called “int-br-eth2” and "phy-br-eth2", this veth pair is used to connect two bridge in OVS "br-eth2" and "br-int". In the previous post we explained how to check the veth connectivity using the ethtool command. It shows that the two are indeed a pair: # ethtool -S int-br-eth2 NIC statistics:      peer_ifindex: 10 . .   #ip link . . 10: phy-br-eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 . . Note that “phy-br-eth2” is connected to a bridge called "br-eth2" and one of this bridge's interfaces is the physical link eth2. This means that the network which we have just created has created a namespace which is connected to the physical interface eth2. eth2 is the “VM network” the physical interface where all the virtual machines connect to where all the VMs are connected. About network isolation: OpenStack supports creation of multiple isolated networks and can use several mechanisms to isolate the networks from one another. The isolation mechanism can be VLANs, VxLANs or GRE tunnels, this is configured as part of the initial setup in our deployment we use VLANs. When using VLAN tagging as an isolation mechanism a VLAN tag is allocated by Neutron from a pre-defined VLAN tags pool and assigned to the newly created network. By provisioning VLAN tags to the networks Neutron allows creation of multiple isolated networks on the same physical link.  The big difference between this and other platforms is that the user does not have to deal with allocating and managing VLANs to networks. The VLAN allocation and provisioning is handled by Neutron which keeps track of the VLAN tags, and responsible for allocating and reclaiming VLAN tags. In the example above net1 has the VLAN tag 1000, this means that whenever a VM is created and connected to this network the packets from that VM will have to be tagged with VLAN tag 1000 to go on this particular network. This is true for namespace as well, if we would like to connect a namespace to a particular network we have to make sure that the packets to and from the namespace are correctly tagged when they reach the VM network. In the example above we see that the namespace interface “tap26c9b807-7c” has vlan tag 1 assigned to it, if we examine OVS we see that it has flows which modify VLAN tag 1 to VLAN tag 1000 when a packet goes to the VM network on eth2 and vice versa. We can see this using the dump-flows command on OVS for packets going to the VM network we see the modification done on br-eth2: #  ovs-ofctl dump-flows br-eth2 NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18669.401s, table=0, n_packets=857, n_bytes=163350, idle_age=25, priority=4,in_port=2,dl_vlan=1 actions=mod_vlan_vid:1000,NORMAL  cookie=0x0, duration=165108.226s, table=0, n_packets=14, n_bytes=1000, idle_age=5343, hard_age=65534, priority=2,in_port=2 actions=drop  cookie=0x0, duration=165109.813s, table=0, n_packets=1671, n_bytes=213304, idle_age=25, hard_age=65534, priority=1 actions=NORMAL   For packets coming from the interface to the namespace we see the following modification: #  ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18690.876s, table=0, n_packets=1610, n_bytes=210752, idle_age=1, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL  cookie=0x0, duration=165130.01s, table=0, n_packets=75, n_bytes=3686, idle_age=4212, hard_age=65534, priority=2,in_port=1 actions=drop  cookie=0x0, duration=165131.96s, table=0, n_packets=863, n_bytes=160727, idle_age=1, hard_age=65534, priority=1 actions=NORMAL   To summarize we can see that when a user creates a network Neutron creates a namespace and this namespace is connected through OVS to the “VM network”. OVS also takes care of tagging the packets from the namespace to the VM network with the correct VLAN tag and knows to modify the VLAN for packets coming from VM network to the namespace. Now let’s see what happens when a VM is launched and how it is connected to the “VM network”. Use case #2: Launch a VM Launching a VM can be done from Horizon or from the command line this is how we do it from Horizon: Attach the network: And Launch Once the virtual machine is up and running we can see the associated IP using the nova list command : # nova list +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | ID                                   | Name         | Status | Task State | Power State | Networks        | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | 3707ac87-4f5d-4349-b7ed-3a673f55e5e1 | Oracle Linux | ACTIVE | None       | Running     | net1=10.10.10.2 | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ The nova list command shows us that the VM is running and that the IP 10.10.10.2 is assigned to this VM. Let’s trace the connectivity from the VM to VM network on eth2 starting with the VM definition file. The configuration files of the VM including the virtual disk(s), in case of ephemeral storage, are stored on the compute node at/var/lib/nova/instances/<instance-id>/. Looking into the VM definition file ,libvirt.xml,  we see that the VM is connected to an interface called “tap53903a95-82” which is connected to a Linux bridge called “qbr53903a95-82”: <interface type="bridge">       <mac address="fa:16:3e:fe:c7:87"/>       <source bridge="qbr53903a95-82"/>       <target dev="tap53903a95-82"/>     </interface>   Looking at the bridge using the brctl show command we see this: # brctl show bridge name     bridge id               STP enabled     interfaces qbr53903a95-82          8000.7e7f3282b836       no              qvb53903a95-82                                                         tap53903a95-82    The bridge has two interfaces, one connected to the VM (“tap53903a95-82 “) and another one ( “qvb53903a95-82”) connected to “br-int” bridge on OVS: # ovs-vsctl show 83c42f80-77e9-46c8-8560-7697d76de51c     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-int         Port br-int             Interface br-int                 type: internal         Port "int-br-eth2"             Interface "int-br-eth2"         Port "qvo53903a95-82"             tag: 3             Interface "qvo53903a95-82"     ovs_version: "1.11.0"   As we showed earlier “br-int” is connected to “br-eth2” on OVS using the veth pair int-br-eth2,phy-br-eth2 and br-eth2 is connected to the physical interface eth2. The whole flow end to end looks like this: VM è tap53903a95-82 (virtual interface)è qbr53903a95-82 (Linux bridge) è qvb53903a95-82 (interface connected from Linux bridge to OVS bridge br-int) è int-br-eth2 (veth one end) è phy-br-eth2 (veth the other end) è eth2 physical interface. The purpose of the Linux Bridge connecting to the VM is to allow security group enforcement with iptables. Security groups are enforced at the edge point which are the interface of the VM, since iptables nnot be applied to OVS bridges we use Linux bridge to apply them. In the future we hope to see this Linux Bridge going away rules.  VLAN tags: As we discussed in the first use case net1 is using VLAN tag 1000, looking at OVS above we see that qvo41f1ebcf-7c is tagged with VLAN tag 3. The modification from VLAN tag 3 to 1000 as we go to the physical network is done by OVS  as part of the packet flow of br-eth2 in the same way we showed before. To summarize, when a VM is launched it is connected to the VM network through a chain of elements as described here. During the packet from VM to the network and back the VLAN tag is modified. Use case #3: Serving a DHCP request coming from the virtual machine In the previous use cases we have shown that both the namespace called dhcp-<some id> and the VM end up connecting to the physical interface eth2  on their respective nodes, both will tag their packets with VLAN tag 1000.We saw that the namespace has an interface with IP of 10.10.10.3. Since the VM and the namespace are connected to each other and have interfaces on the same subnet they can ping each other, in this picture we see a ping from the VM which was assigned 10.10.10.2 to the namespace: The fact that they are connected and can ping each other can become very handy when something doesn’t work right and we need to isolate the problem. In such case knowing that we should be able to ping from the VM to the namespace and back can be used to trace the disconnect using tcpdump or other monitoring tools. To serve DHCP requests coming from VMs on the network Neutron uses a Linux tool called “dnsmasq”,this is a lightweight DNS and DHCP service you can read more about it here. If we look at the dnsmasq on the control node with the ps command we see this: dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap26c9b807-7c --except-interface=lo --pid-file=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host --dhcp-optsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/opts --leasefile-ro --dhcp-range=tag0,10.10.10.0,static,120s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal The service connects to the tap interface in the namespace (“--interface=tap26c9b807-7c”), If we look at the hosts file we see this: # cat  /var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host fa:16:3e:fe:c7:87,host-10-10-10-2.openstacklocal,10.10.10.2   If you look at the console output above you can see the MAC address fa:16:3e:fe:c7:87 which is the VM MAC. This MAC address is mapped to IP 10.10.10.2 and so when a DHCP request comes with this MAC dnsmasq will return the 10.10.10.2.If we look into the namespace at the time we initiate a DHCP request from the VM (this can be done by simply restarting the network service in the VM) we see the following: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c tcpdump -n 19:27:12.191280 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:fe:c7:87, length 310 19:27:12.191666 IP 10.10.10.3.bootps > 10.10.10.2.bootpc: BOOTP/DHCP, Reply, length 325   To summarize, the DHCP service is handled by dnsmasq which is configured by Neutron to listen to the interface in the DHCP namespace. Neutron also configures dnsmasq with the combination of MAC and IP so when a DHCP request comes along it will receive the assigned IP. Summary In this post we relied on the components described in the previous post and saw how network connectivity is achieved using three simple use cases. These use cases gave a good view of the entire network stack and helped understand how an end to end connection is being made between a VM on a compute node and the DHCP namespace on the control node. One conclusion we can draw from what we saw here is that if we launch a VM and it is able to perform a DHCP request and receive a correct IP then there is reason to believe that the network is working as expected. We saw that a packet has to travel through a long list of components before reaching its destination and if it has done so successfully this means that many components are functioning properly. In the next post we will look at some more sophisticated services Neutron supports and see how they work. We will see that while there are some more components involved for the most part the concepts are the same. @RonenKofman

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• Access Control Service v2: Registering Web Identities in your Applications [concepts]

  - by Your DisplayName here!

  ACS v2 support two fundamental types of client identities– I like to call them “enterprise identities” (WS-*) and “web identities” (Google, LiveID, OpenId in general…). I also see two different “mind sets” when it comes to application design using the above identity types: Enterprise identities – often the fact that a client can present a token from a trusted identity provider means he is a legitimate user of the application. Trust relationships and authorization details have been negotiated out of band (often on paper). Web identities – the fact that a user can authenticate with Google et al does not necessarily mean he is a legitimate (or registered) user of an application. Typically additional steps are necessary (like filling out a form, email confirmation etc). Sometimes also a mixture of both approaches exist, for the sake of this post, I will focus on the web identity case. I got a number of questions how to implement the web identity scenario and after some conversations it turns out it is the old authentication vs. authorization problem that gets in the way. Many people use the IsAuthenticated property on IIdentity to make security decisions in their applications (or deny user=”?” in ASP.NET terms). That’s a very natural thing to do, because authentication was done inside the application and we knew exactly when the IsAuthenticated condition is true. Been there, done that. Guilty ;) The fundamental difference between these “old style” apps and federation is, that authentication is not done by the application anymore. It is done by a third party service, and in the case of web identity providers, in services that are not under our control (nor do we have a formal business relationship with these providers). Now the issue is, when you switch to ACS, and someone with a Google account authenticates, indeed IsAuthenticated is true – because that’s what he is! This does not mean, that he is also authorized to use the application. It just proves he was able to authenticate with Google. Now this obviously leads to confusion. How can we solve that? Easy answer: We have to deal with authentication and authorization separately. Job done ;) For many application types I see this general approach: Application uses ACS for authentication (maybe both enterprise and web identities, we focus on web identities but you could easily have a dual approach here) Application offers to authenticate (or sign in) via web identity accounts like LiveID, Google, Facebook etc. Application also maintains a database of its “own” users. Typically you want to store additional information about the user In such an application type it is important to have a unique identifier for your users (think the primary key of your user database). What would that be? Most web identity provider (and all the standard ACS v2 supported ones) emit a NameIdentifier claim. This is a stable ID for the client (scoped to the relying party – more on that later). Furthermore ACS emits a claims identifying the identity provider (like the original issuer concept in WIF). When you combine these two values together, you can be sure to have a unique identifier for the user, e.g.: Facebook-134952459903700\799880347 You can now check on incoming calls, if the user is already registered and if yes, swap the ACS claims with claims coming from your user database. One claims would maybe be a role like “Registered User” which can then be easily used to do authorization checks in the application. The WIF claims authentication manager is a perfect place to do the claims transformation. If the user is not registered, show a register form. Maybe you can use some claims from the identity provider to pre-fill form fields. (see here where I show how to use the Facebook API to fetch additional user properties). After successful registration (which may include other mechanisms like a confirmation email), flip the bit in your database to make the web identity a registered user. This is all very theoretical. In the next post I will show some code and provide a download link for the complete sample. More on NameIdentifier Identity providers “guarantee” that the name identifier for a given user in your application will always be the same. But different applications (in the case of ACS – different ACS namespaces) will see different name identifiers. This is by design to protect the privacy of users because identical name identifiers could be used to create “profiles” of some sort for that user. In technical terms they create the name identifier approximately like this: name identifier = Hash((Provider Internal User ID) + (Relying Party Address)) Why is this important to know? Well – when you change the name of your ACS namespace, the name identifiers will change as well and you will will lose your “connection” to your existing users. Oh an btw – never use any other claims (like email address or name) to form a unique ID – these can often be changed by users.

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• Sass interface in HTML6 for upload files.

  - by Anirudha

  Originally posted on: http://geekswithblogs.net/anirugu/archive/2013/11/04/sass-interface-in-html6-for-upload-files.aspx[This post is about experiment & imagination] From Windows XP (ever last OS I tried) I have seen a feature that is about send file to pen drive and make shortcut on Desktop. In XP, Win7 (Win8 have this too, not removed) just select the file right click > send to and you can send this file to many places. In my menu it’s show me Skype because I have installed it. this skype confirm that we can add our own app here to make it more easy for user to send file in our app. Nowadays Many people use Cloud or online site to store the file. In case of html5 drag and drop you need to have site opened and have opened that page which is about file upload. You need to select all  and drag and drop. after drag and drop file is simply uploaded to server and site show you on list (if no error happen). but this file upload is seriously not worthy since I have to open the site when I do this operation.   Through this post I want to describe a feature that can make this thing better.  This API is simply called SASS FILE UPLOAD API Through This API when you surf the site and come into file upload page then the page will tell you that we also have SASS FILE API support. Enable it for better result.   How this work This API feature are activated on 2 basis. 1. Feature are disabled by default on site (or you can change it if it’s not) 2. This API allow specific site to upload the files. Files upload may have some rule. For example (minimum or maximum size of file to uploaded, which format the site allowed you to upload). In case of resume site you will be allowed to use .doc (according to code of site)   How browser recognize that Site have SASS service. In HTML source of  the site, the code have a meta tag similar to this <meta name=”sass-upload-api” path=”/upload.json”/> Remember that upload.json is one file that has define the value of many settings {   "cookie_name": "ck_file",   "maximum_allowed_perday": 24,   "allowed_file_extensions","*.png,*.jpg,*.jpeg,*.gif",   "method": [       {           "get": "file/get",           "routing":"/file/get/{fileName}"       },       {           "post": "file/post",           "routing":"/file/post/{fileName}"       },       {           "delete": "file/delete",           "routing":"/file/delete/{fileName}"       },         {           "put": "file/put",           "routing":"/file/put/{fileName}"       },        {           "all": "file/all",           "routing":"/file/all/{fileName}"       }    ] } cookie name is simply a cookie which should be stored in browser and define in json. we define the cookie_name so we can easily share then with service in Windows system. This cookie will be accessible with the service so it’s security based safe. other cookie will not be shared.   The cookie will be post,put, get from this location. The all location will be simply about showing a whole list of file. This will gave a treeview kind of json to show the directories on sever.   for example example.com if you have activated the API with this site then you will seen a send to option in your explorer.exe when you send you will got a windows open which folder you want to use to send the file. The windows will also describe the limit and how much you can upload. This thing never required site to opened. When you upload the file this will be uploaded through FTP protocol. FTP protocol are better for performance.   How this API make thing faster. Suppose you want to ask a question and want to post image. you just do it and get it ready when you open stackoverflow.com now stackoverflow will only tell you which file you want to put on your current question that you asking for. second use is about people use cloud app.   There is no need of drag and drop anymore. we just need to do it without drag and drop it. we doesn’t need to open the site either. This thing is still in experiment level. I will update this post when I got some progress on this API.

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• Control HelpButton, HelpRequested, HelpButtonClicked - Instant help for windows Dialog Form components

  Instant help for windows dialog components is a great feature and very much known since windows 98. but I saw many many people are not aware it and query on Google to get help, but “help button” for dialogs helps you or your customers to get the help instantly. Every dialog window has help icon if that dialog was coded to enable it. it really helps to know the functionality of the components quickly. For example I was trying to pint a document from acrobat reader and opened printer properties to print the content front and back of the paper. If you observe there is a help button before close button. To get help on options of “Print on Both Sides” you would need to click on help button first and then click on the area on which you want to see the help. above picture shows help text for the options of “Print on Both Sides”. If you would like to get the help using keyboard you can use F1 key. Help button can be displayed only if minimize button and maximize button both are not shown unless you want go with custom buttons. below is the way if you want to get Help button for windows forms.   In this sample demo I want to have a checkbox and need to show help when I click on F1 on check box. So I created a form which country check box and help label as show in adjacent picture. Below is the code for your code bind file. using System; using System.Windows.Forms; namespace WindowsFormsApplication1 {     public partial classForm1: Form    {         publicForm1()         {             InitializeComponent();         }         private void Form1_Load(objectsender, EventArgs e)         {             this.Text = "Help Button Demo Form";             lblHelp.Text = "Press F1 on any component to get Instant Help";             this.HelpButton = true;             this.MaximizeBox = false;             this.MinimizeBox = false;             chkCountry.Tag = "Check or Uncheck Coutry Check Box";             chkCountry.HelpRequested += newHelpEventHandler(chkCountry_HelpRequested);             chkCountry.MouseLeave += newEventHandler(chkCountry_MouseLeave);         }         void chkCountry_HelpRequested(objectsender, HelpEventArgs hlpevent)         {             ControlrequestingControl = (Control)sender;             lblHelp.Text = (string)requestingControl.Tag;             hlpevent.Handled = true;         }         void chkCountry_MouseLeave(objectsender, EventArgs e)         {             lblHelp.Text = "Press F1 on any component to get Instant Help";         }     } } In above code  “HelpRequested” is an event will be fired when you click on F1 on Country checkbox. I stored the help information in the checkbox property called “Tag”. You might also maintain a property file to keep help text for each component differently. If you click on F1 when focus is on main form instead on individual component then generally separate help window opens. This can be done using the event “Form.HelpRequested” to open help windows as in below code. this.HelpRequested += newHelpEventHandler(Form1_HelpRequested); voidForm1_HelpRequested(objectsender, HelpEventArgs hlpevent) {     frmHelp.Show(); } span.fullpost {display:none;}

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• c# display DB table structure

  - by user3529643

  I have a question. My code is the following : public partial class Form1 : Form { public OleDbConnection datCon; public string MyDataFile; public ArrayList tblArray; public ArrayList fldArray; public Form1() { InitializeComponent(); lvData.Clear(); lvData.View = View.Details; lvData.LabelEdit = false; lvData.FullRowSelect = true; lvData.GridLines = true; } private void DataConnection() { MyDataFile = Application.StartupPath + @"\studenti.mdb"; string MyCon = @"provider=microsoft.jet.oledb.4.0;data source=" + MyDataFile; try { datCon = new OleDbConnection(MyCon); } catch (Exception ex) { MessageBox.Show(ex.Message); } FillTreeView(); } private void GetTables(OleDbConnection cnn) { try { cnn.Open(); DataTable schTable = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new Object[] { null, null, null, "TABLE" }); tblArray = new ArrayList(); foreach (DataRow datrow in schTable.Rows) { tblArray.Add(datrow["TABLE_NAME"].ToString()); } cnn.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void GetFields(OleDbConnection cnn, string tabNode) { string tabName; try { tabName = tabNode; cnn.Open(); DataTable schTable = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new Object[] { null, null, tabName }); fldArray = new ArrayList(); foreach (DataRow datRow in schTable.Rows) { fldArray.Add(datRow["COLUMN_NAME"].ToString()); } cnn.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void FillTreeView() { tvData.Nodes.Clear(); tvData.Nodes.Add("Database"); tvData.Nodes[0].Tag = "RootDB"; GetTables(datCon); // add table node for (int i = 0; i < tblArray.Count; i++) { tvData.Nodes[0].Nodes.Add(tblArray[i].ToString()); tvData.Nodes[0].Nodes[i].Tag = "Tables"; } // add field node for (int i = 0; i < tblArray.Count; i++) { GetFields(datCon, tblArray[i].ToString()); for (int j = 0; j < fldArray.Count; j++) { tvData.Nodes[0].Nodes[i].Nodes.Add(fldArray[j].ToString()); tvData.Nodes[0].Nodes[i].Nodes[j].Tag = "Fields"; } } this.tvData.ContextMenuStrip = contextMenuStrip1; contextMenuStrip1.ItemClicked +=contextMenuStrip1_ItemClicked; } public void FillListView(OleDbConnection cnn, string tabName) { OleDbCommand cmdRead; OleDbDataReader datReader; string strField; lblTableName.Text = tabName; strField = "SELECT * FROM [" + tabName + "]"; // Initi cmdRead obiect cmdRead = new OleDbCommand(strField, cnn); cnn.Open(); datReader = cmdRead.ExecuteReader(); // fill ListView while (datReader.Read()) { ListViewItem objListItem = new ListViewItem(datReader.GetValue(0).ToString()); for (int c = 1; c < datReader.FieldCount; c++) { objListItem.SubItems.Add(datReader.GetValue(c).ToString()); } lvData.Items.Add(objListItem); } datReader.Close(); cnn.Close(); } private void ViewToolStripMenuItem_Click(object sender, EventArgs e) { DataConnection(); } public void tvData_AfterExpand(object sender, System.Windows.Forms.TreeViewEventArgs e) { string tabName; int fldCount; if (e.Node.Tag.ToString() == "Tables") { fldCount = e.Node.GetNodeCount(false); //column headers. int n = lvData.Width; double wid = n / fldCount; // width columnn for (int c = 0; c < fldCount; c++) { lvData.Columns.Add(e.Node.Nodes[c].Text, (int)wid, HorizontalAlignment.Left); } // gett table name tabName = e.Node.Text; FillListView(datCon, tabName); } } public void button1_Click(object sender, EventArgs e) { //TO DO?? } } I have a treeview populated with tables (nodes) from my database, and a listview which is populated with the data from my tables when I click on a table. As you can see I have a button1 on my form. When I click it I want it to display to me the structure of the table I selected in my treeview (a treeview node). Not too many details, just the name of the columns in my table, type of columns, primary keys. I've tried to follow many tutorials but I can t seem to manage it.

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• Can I use Silverlight 3 third party controls with Silverlight 4

  - by Sergey Mirvoda

  Recently I installed Silverlight 4 plugin and noticed that windowless mode now works correctly with FireFox. I quickly read SL4 release notes but cannot find answer. Can I use SL3 controls (we are using a LOT of DevExpress and Infragistics controls) in SL4.

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• Create Audio file on iPhone/iPad from many other audio files (mixer)

  - by Brian

  I am trying to create something similar like Piano app on the iPhone. When people tap a key, it play a piano note. Basically, there will have only 7 notes (C) at the moment. Each note is a .caf file and its length is 5 seconds. I do not know if there is any way to save the song user played and export to mp3/caf format? The AVAudioRecord seems only record from the microphone input. Many thanks

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• Django syncdb error

  - by Hulk

  /mysite/project4 class notes(models.Model): created_by = models.ForeignKey(User) detail = models.ForeignKey(Details) Details and User are in the same module i.e,/mysite/project1 In project1 models i have defined class User(): ...... class Details(): ...... When DB i synced there is an error saying Error: One or more models did not validate: project4: Accessor for field 'detail' clashes with related field . Add a related_name argument to the definition for 'detail'. How can this be solved.. thanks..

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• DDD with Grails

  - by Paul

  I cannot find any info about doing Domain Driven Design (DDD) with Grails. I'm looking for any best practices, experience notes or even open source projects that are good examples of DDD with Grails.

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• Why isn't ValidateRequest="true" enough for XSS prevention?

  - by Microserf

  In the notes for Step 1 in the "How To: Prevent Cross-Site Scripting in ASP.NET" it is stated that you should "not rely on ASP.NET request validation. Treat it as an extra precautionary measure in addition to your own input validation." Why isn't it enough?

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• Have you used Intersystems Caché? What is your experience?

  - by user49767

  I came across few claims that usage of CacheDB instead of prooven RDBMS. But I couldn't understand how it is better than RDBMS? if so, why do they prefixed with Cache? Is it RDBMS or Caché server? Could you write brief notes about the use-case in your project?

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• How do you keep a personal wiki (TiddlyWiki) current and in sync in multiple locations?

  - by sal

  If one were to use TiddlyWiki as a personal database for notes and code snippets, how would you go about keeping it in sync between multiple machines. Would a svn/cvs etc work. How would you handle merges?

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• StackOverflow Google Gadget [closed]

  - by AdamC

  I created a very quick Google Desktop gadget to track a user's reputation on SO. It takes only a user's ID (user name won't work) and shows the current reputation and gives notifications (if enabled) on any changes. It occurred to me that it might be useful to others here both for tracking and if you wanted to know how to create a gadget. Download the gadget A few notes about creating it

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• Drawing A Piano

  - by Jonathan M.

  Hello Everyone, I have started working on a software synthesizer (or keyboard). I have decided to use Java because of the available Jfugue API. I am trying to figure out how to go about creating the actual keys (notes) of the keyboard user interface, but I am stuck. I have tried to create an interface by dragging/dropping black and white rectangular buttons onto the panel, but that doesn't seem to work. Could someone point me into the right direction?

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• How to bulk insert from CSV when some fields have new line character?

  - by z-boss

  I have a CSV dump from another DB that looks like this (id, name, notes): 1001,John Smith,15 Main Street 1002,Jane Smith,"2010 Rockliffe Dr. Pleasantville, IL USA" 1003,Bill Karr,2820 West Ave. The last field may contain carriage returns and commas, in which case it is surrounded by double quotes. I use this code to import CSV into my table: BULK INSERT CSVTest FROM 'c:\csvfile.csv' WITH ( FIELDTERMINATOR = ',', ROWTERMINATOR = '\n' ) SQL Server 2005 bulk insert cannot figure out that carriage returns inside quotes are not row terminators. How to overcome?

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• Symfony forms: how to set default value for a textarea widget

  - by morpheous

  I am using Symfony 1.3.2 on Ubuntu 9.10 I want to set the default value of a textarea widget, with data read froma adb. My code snippet in the template looks likes this: <?php $form['notes']->render(); ?> The API docs dont show how to do this - does anyone know how to do this?

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• How to determine the longest increasing subsequence using dynamic programming?

  - by Tony

  Let's say I have a set of integers. I want to find the longest increasing subsequence of that set using dynamic programming. This is simply out of practice, reviewing my old notes from my algorithms course, and I don't seem to understand how this works. Thanks

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