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• Access Control Service: Programmatically Accessing Identity Provider Information and Redirect URLs

  - by Your DisplayName here!

  In my last post I showed you that different redirect URLs trigger different response behaviors in ACS. Where did I actually get these URLs from? The answer is simple – I asked ACS ;) ACS publishes a JSON encoded feed that contains information about all registered identity providers, their display names, logos and URLs. With that information you can easily write a discovery client which, at the very heart, does this: public void GetAsync(string protocol) {     var url = string.Format( "https://{0}.{1}/v2/metadata/IdentityProviders.js?protocol={2}&realm={3}&version=1.0",         AcsNamespace,         "accesscontrol.windows.net",         protocol,         Realm);     _client.DownloadStringAsync(new Uri(url)); } The protocol can be one of these two values: wsfederation or javascriptnotify. Based on that value, the returned JSON will contain the URLs for either the redirect or notify method. Now with the help of some JSON serializer you can turn that information into CLR objects and display them in some sort of selection dialog. The next post will have a demo and source code.

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• Angry Birds and Star Wars Join Forces for an Awesome New Edition [Plus Wallpaper!]

  - by Asian Angel

  Are you ready for a new version of Angry Birds? Then rejoice, you are less than a month away from an awesome new release of everyone’s favorite bird-slinging, pig smashing game! Prepare for a journey to a galaxy far, far away… From the blog post: From the deserts of Tatooine to the depths of the Death Star – the game and merchandise will feature the Angry Birds characters starring as the iconic heroes of the beloved Saga. In the coming weeks, fans can expect additional new videos, characters, and much more exciting content to be revealed. The game will be available on iOS, Android, Amazon Kindle Fire, Mac, PC, Windows Phone and Windows 8. Here is the first of the promo videos for the new version. Also, make sure to download the first official wallpaper (linked to below)! How To Get a Better Wireless Signal and Reduce Wireless Network Interference How To Troubleshoot Internet Connection Problems 7 Ways To Free Up Hard Disk Space On Windows

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• Access Control Service: Handling Errors

  - by Your DisplayName here!

  Another common problem with external authentication is how to deal with sign in errors. In active federation like WS-Trust there are well defined SOAP faults to communicate problem to a client. But with web applications, the error information is typically generated and displayed on the external sign in page. The relying party does not know about the error, nor can it help the user in any way. The Access Control Service allows to post sign in errors to a specified page. You setup this page in the relying party registration. That means that whenever an error occurs in ACS, the error information gets packaged up as a JSON string and posted to the page specified. This way you get structued error information back into you application so you can display a friendlier error message or log the error. I added error page support to my ACS2 sample, which can be downloaded here. How to turn the JSON error into CLR types The JSON schema is reasonably simple, the following class turns the JSON into an object: [DataContract] public class AcsErrorResponse {     [DataMember(Name = "context", Order = 1)]     public string Context { get; set; }     [DataMember(Name = "httpReturnCode", Order = 2)]     public string HttpReturnCode { get; set; }     [DataMember(Name = "identityProvider", Order = 3)]        public string IdentityProvider { get; set; }     [DataMember(Name = "timeStamp", Order = 4)]     public string TimeStamp { get; set; }     [DataMember(Name = "traceId", Order = 5)]     public string TraceId { get; set; }     [DataMember(Name = "errors", Order = 6)]     public List<AcsError> Errors { get; set; }     public static AcsErrorResponse Read(string json)     {         var serializer = new DataContractJsonSerializer( typeof(AcsErrorResponse));         var response = serializer.ReadObject( new MemoryStream(Encoding.Default.GetBytes(json))) as AcsErrorResponse;         if (response != null)         {             return response;         }         else         {             throw new ArgumentException("json");         }     } } [DataContract] public class AcsError {     [DataMember(Name = "errorCode", Order = 1)]     public string Code { get; set; }             [DataMember(Name = "errorMessage", Order = 2)]     public string Message { get; set; } } Retrieving the error information You then need to provide a page that takes the POST and deserializes the information. My sample simply fills a view that shows all information. But that’s for diagnostic/sample purposes only. You shouldn’t show the real errors to your end users. public class SignInErrorController : Controller {     [HttpPost]     public ActionResult Index()     {         var errorDetails = Request.Form["ErrorDetails"];         var response = AcsErrorResponse.Read(errorDetails);         return View("SignInError", response);     } } Also keep in mind that the error page is an anonymous page and that you are taking external input. So all the usual input validation applies.

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• Access Control Service: Walkthrough Videos of Web Application, SOAP, REST and Silverlight Integration

  - by Your DisplayName here!

  Over the weekend I worked a little more on my ACS2 sample. Instead of writing it all down, I decided to quickly record four short videos that cover the relevant features and code. Have fun ;) Part 1 – Overview This video does a quick walkthrough of the solution and shows the web application part. This includes driving the sign in UI via JavaScript (thanks Matias) as well as the registration logic I wrote about here. watch Part 2 – SOAP Service and Client The sample app also exposes a WCF SOAP service. This video shows how to wire up the service to ACS and hows how to create a client that first requests a token from an IdP and then sends this token to ACS. watch Part 3 – REST Service and Client This part shows how to set up a WCF REST service that consumes SWT tokens from ACS. Unfortunately there is currently no standard WIF plumbing for REST. For the service integration I had to combine a lot of code from different sources (kzu, zulfiq) as well as the WIF SDK and OAuth CTPs together. But it is working. watch Part 4 – Silverlight and Web Identity Integration This part took by far the most time to write. The Silverlight Client shows ho to sign in to the application using a registered identity provider (including web identities) and using the resulting SWT token to call our REST service. This is designed to be a desktop (OOB) client application (thanks to Jörg for the UI magic). watch code download

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

  - by Your DisplayName here!

  You can download the full solution here. The relevant parts in the sample are: Configuration I use the standard WIF configuration with passive redirect. This kicks automatically in, whenever authorization fails in the application (e.g. when the user tries to get to an area the requires authentication or needs registration). Checking and transforming incoming claims In the claims authentication manager we have to deal with two situations. Users that are authenticated but not registered, and registered (and authenticated) users. Registered users will have claims that come from the application domain, the claims of unregistered users come directly from ACS and get passed through. In both case a claim for the unique user identifier will be generated. The high level logic is as follows: public override IClaimsPrincipal Authenticate( string resourceName, IClaimsPrincipal incomingPrincipal) {     // do nothing if anonymous request     if (!incomingPrincipal.Identity.IsAuthenticated)     {         return base.Authenticate(resourceName, incomingPrincipal);     } string uniqueId = GetUniqueId(incomingPrincipal);     // check if user is registered     RegisterModel data;     if (Repository.TryGetRegisteredUser(uniqueId, out data))     {         return CreateRegisteredUserPrincipal(uniqueId, data);     }     // authenticated by ACS, but not registered     // create unique id claim     incomingPrincipal.Identities[0].Claims.Add( new Claim(Constants.ClaimTypes.Id, uniqueId));     return incomingPrincipal; } User Registration The registration page is handled by a controller with the [Authorize] attribute. That means you need to authenticate before you can register (crazy eh? ;). The controller then fetches some claims from the identity provider (if available) to pre-fill form fields. After successful registration, the user is stored in the local data store and a new session token gets issued. This effectively replaces the ACS claims with application defined claims without requiring the user to re-signin. Authorization All pages that should be only reachable by registered users check for a special application defined claim that only registered users have. You can nicely wrap that in a custom attribute in MVC: [RegisteredUsersOnly] public ActionResult Registered() {     return View(); } HTH

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• Small (and fixed) Bug in IdentityServer v1.0

  - by Your DisplayName here!

  It was brought to my attention that fedutil does not work anymore with IdSrv v1 metadata. And I can confirm that. The reason for this bug is my recent change to the XmlWriter factory methods which have a different default behavior when it comes to encoding. Since there were only 20 downloads so far – I fixed the bug in-place (shame on me). So when you are one of the early adopters and run into this problem – just re-download IdSrv ;) HTH

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• StarterSTS 1.1 CTP &ndash; ActAs Support

  - by Your DisplayName here!

  Due to popular demand, I added identity delegation (aka ActAs) support to StarterSTS. To give this feature a try, first download the new bits and add a enableActAs = true to startersts.config. You then have to configure which user account is allowed to delegate, as well as the target realm to delegate to. This is done in usermappings.config, e.g.: <userMappings xmlns="http://www.thinktecture.com/configuration/usermappings">     <user name="middletier">       <mappings>         <mapping type="ActAs"                  value="https://server/service.svc" />       </mappings>     </user>   </users> </userMappings> Please use the forum for any feedback. thanks!

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• After power manager reinstall

  - by tuxi

  I had checking battery state hanging I solved it with the help of an answer from this site: sudo apt-get --reinstall install gnome-power-manager But now my left windows bar is rigid, it does not disappear on wide screen. EDIT Also in most of applications, characters are white. What could be the problem? and what should I do? 2ND EDIT My ubuntu is 12.04 LTS. I was trying to install some packages for dependencies of allegro game development library, one of the packages was libwxgtk2.8-0, after that a red cross appeared near user name and clock. Then computer became frozen and i had to remove my battery. I know it is a very bad thing. Then when i try to restart my computer, it could not start, it was waiting on black screen with line: Checking battery state... Then i run the above command. Computer could start but characters are white.

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• current_user.user_type_id = @employer ID

  - by sscirrus

  I am building a system with a User model (authenticated using AuthLogic) and three user types in three models: one of these models is Employer. Each of these three models has_many :users, :as = :authenticable. I start by having a new visitor to the site create their own 'User' record with username, password, which user type they are, etc. Upon creation, the user is sent to the 'new' action for one of the three models. So, if they tell us they are an employer, we redirect_to :controller = "employers, :action = "new". Question: When the employer has submitted, I want to set the current_user.user_type_id equal to the employer ID. This should be simple... but it's not working. # Employers Controller / new def new @employer = Employer.new 1.times {@employer.addresses.build} render :layout => 'forms' end # Employers Controller / create def create @employer = Employer.new(params[:employer]) if @employer.save if current_user.blank? redirect_to :controller => "users", :action => "new" else current_user.user_type_id = @employer.id current_user.user_type = "Employer" redirect_to :action => "home", :id => current_user.user_type_id end else render :action => "new" end end ------UPDATE------ Hi guys. In response: I am using this table structure because each of my three user type models have lots of different fields and each has different relationships to the other models, which is why I've avoided STI. By 1.times (@employer.addresses.build) I'm connecting the employer model to the address polymorphic table in one form, so I'm asking the controller to build a new address to go along with the new employer. Averell: you mentioned encapsulating... something in the model using a 'setter' method. I have no idea what you mean by this - could you please explain how this works (or direct me to an example elsewhere)? With tsdbrown's answer I have managed to create the behavior I want... if there's a more elegant way to accomplish the same thing I'd love to learn how. Thanks very much. Thanks to tsdbrown for answering the current_user.save problem!

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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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• "Index of ..." directory's files listing

  - by Tony

  On my courses we've got homework on site in folders such as: http://example.com/files/tasks1-edc34rtgfds http://example.com/files/tasks2-0bg454fgerg http://example.com/files/tasks3-h1dlkjiojo8 ... Each tasksi-xxxxxxxxxxx is a folder with 11 random characters at the end. And when you view the above URLs in browser you can see Index of /tasksi-xxxxxxxxx with all the files in that folder. When you view http://example.com/files/ you can see only empty html with words "Hello, world". The problem is that you can't look into the next task without knowledge of its URL. So for example we've got the URLs for tasks1 and tasks2, and we can't guess what tasks3 URL will be (as we need to know the 11 random characters at the end) How can I get the list of all directories? (Is there a way to type something like http://example.com/files/task1-aflafjal343/..? or another way?) I want to see all upcoming homework tasks.

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• Guide to Claims-based Identity and Access Control (2nd Edition)

  - by Your DisplayName here!

  This fell through the cracks over the summer holiday time: The 2nd edition of the Patterns & Practices “claims guide” has been released. This is excellent! We added a lot of content around ADFS, Access Control Service, REST and SharePoint. All source code is available as well! Grab it from: http://msdn.microsoft.com/en-us/library/ff423674.aspx Or use my vanity URL: http://tinyurl.com/claimsguide

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• Long lines of text in source code [closed]

  - by ale

  Possible Duplicate: Is the 80 character limit still relevant in times of widescreen monitors? I used to set a vertical line set at 80 characters in my text editor and then I added carriage returns if the lines got too long. I later increased the value to 135 characters. I started using word wrap and not giving myself a limit but tried to keep lines short if I could because it took a lot of time shortening my lines. People at work use word wrap and don't give themselves a limit.. is this the correct way? What are you meant to do ? Many thanks.

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• Is a blob more efficient than a varchar for data that can be ANY size?

  - by BillyNair

  When setting up a database I want to use the most efficient data type for potentially fairly long data. Currently my project is to store song titles and thoughts pertaining to that song. Some titles might be 5 characters or longer than 100 characters and the thoughts could run pretty long. Is it more efficient to use a varchar set to 8000 or to use a blob? Is using a blob the same as a varchar, in that there is a set size it is allocated regardless of what it holds? or is it just a pointer and it doesn't really use much space on the table? Is there a certain set size of a blob in KB or is it expandable?

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• C++ function returning pointer, why does this work ? [migrated]

  - by nashmaniac

  So heres a simple c++ function what it does it take an array of characters as its argument and a integer n and then creates a new character array with only n elements of the array. char * cutString(char * ch , int n){ char * p = new char[n]; int i ; for(i = 0 ; i < n ; i++) p[i] = ch[i]; while(i <= n ){ p[i++] = '\0'; } return p ; } this works just fine but if I change char * p = new char[n]; to char p[n]; I see funny characters what happens ? What difference does the former make also p is a temporary variable then how does the function returns it alright ?

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• WIF in .NET 4.5&ndash;First Observations (2)

  - by Your DisplayName here!

    WindowsIdentity, FormsIdentity and GenericIdentity now derive from ClaimsIdentity WindowsIdentity.GetCurrent() converts Windows token details (groups for the current Windows versions) to claims. Claims for Windows identities now distinguish between user claims and device claims (Windows 8 feature) WCF now populates Thread.CurrentPrincipal with a ClaimsPrincipal derived type

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• IPv6: Should I have private addresses?

  - by AlReece45

  Right now, we have a rack of servers. Every server right now has at least 2 IP addresses, one for the public interface, another for the private. The servers that have SSL websites on them have more IP addresses. We also have virtual servers, that are configured similarly. Private Network The private range is currently just used for backups and monitoring. Its a gigabit port, the interface usage does not usually get very high. There are other technologies we're considering using that would use this port: iSCSI (implementations usually recommends dedicating an interface to it, which would be yet another IP network), VPN to get access to the private range (something I'd rather avoid) dedicated database servers LDAP centralized configuration (like puppet) centralized logging We don't have any private addresses in our DNS records (only public addresses). For our servers to utilize the correct IP address for the right interface (and not hard code the IP address) probably requires setting up a private DNS server (So now we add 2 different dns entries to 2 different systems). Public Network Our public range has a variety of services include web, email, and ftp. There is a hardware firewall between our network and the "public" network. We have (relatively secure) method to instruct the firewall to open and close administrative access (web interfaces, ssh, etc) for our current IP address. With either solution discussed, the host-based firewalls will be configured as well. The public network currently runs at a dedicated 20Mbps link. There are a couple of legacy servers with fast-ethernet ports, but they are scheduled for decommissioning. All of the other production boxes have at least 2 Gigabit Ethernet ports. The more traffic-heavy servers have 4-6 available (none is using more than the 2 Gigabit ports right now). IPv6 I want to get an IPv6 prefix from our ISP. So at least every "server" has at least one IPv6 interface. We'll still need to keep the IPv4 addressees up and available for legacy clients (web servers and email at the very least). We have two IP networks right now. Adding the public IPv6 address would make it three. Just use IPv6? I'm thinking about just dumping the private IPv4 range and using the IPv6 range as the primary means of all communications. If an interface starts reaching its capacity, utilize the newly free interfaces to create a trunk. It has the advantage that if either the public or private traffic needs to exceed 1Gbps. The traffic for each interface is already analyzed on a regular basis to predict future bandwidth use. In the rare instances where bandwidth unexpected peaks: utilize QoS to ensure traffic (like our limited SSH access) is prioritized correctly so the problem can be corrected (if possible, our WAN is the bottleneck right now). It also has the advantage of not needing to make an entry for every private address. We may have private DNS (or just LDAP), but it'll be much more limited in scope with less entries to duplicate. Summary I'm trying to make this network as "simple" as possible. At the same time, I want to make sure its reliable, upgradeable, scalable, and (eventually) redundant. Having one IPv6 network, and a legacy IPv4 network seems to be the best solution to me. Regarding using assigned IPv6 addresses for both networks, sharing the available bandwidth on one (more trunked if needed): Are there any technical disadvantages (limitations, buffers, scalability)? Are there any other security considerations (asides from firewalls mentioned above) to consider? Are there regulations or other security requirements (like PCI-DSS) that this doesn't meet? Is there typical software for setting up a Linux network that doesn't have IPv6 support yet? (logging, ldap, puppet) Some other thing I didn't consider?

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• Java Developer Days India Trip Report

  - by reza_rahman

  You are probably aware of Oracle's decision to discontinue the relatively resource intensive regional JavaOnes in favor of more Java Developer Days, virtual events and deeper involvement with independent conferences. In comparison to the regional JavaOnes, Java Developer Days are smaller, shorter (typically one full day), more focused (mostly Oracle speakers/topics) and more local (targeting cities). For those who have been around the Java ecosystem for a few years, they are basically the current incarnation of the highly popular and developer centric Sun Tech Days. October 21st through October 25th I spoke at Java Developer Days India. This was basically three separate but identical events in the cities of Pune (October 21st), Chennai (October 24th) and Bangalore (October 25th). For those with some familiarity with India, other than Hyderabad these cities are India's IT powerhouses. The events were basically focused on Java EE. I delivered five of the sessions (yes, you read that right), while my friend NetBeans Group Product Manager Ashwin Rao delivered three talks. Jagadish Ramu from the GlassFish team India helped me out in Bangalore by delivering two sessions. It was also a pleasure to introduce my co-contributor to the Cargo Tracker Java EE Blue Prints project Vijay Nair at Bangalore during the opening talk. I thought it was a great dynamic between Ashwin and I flipping between talking about the new features and demoing live code in NetBeans. The following were my sessions (source PDF and abstracts posted as usual on my SlideShare account): JavaEE.Next(): Java EE 7, 8, and Beyond Building Java HTML5/WebSocket Applications with JSR 356 What’s New in Java Message Service 2 JAX-RS 2: New and Noteworthy in the RESTful Web Services API Using NoSQL with JPA, EclipseLink and Java EE The event went well and was packed in all three cities. The Q&A was great and Indian developers were particularly generous with kind words :-). It seemed the event and our presence was appreciated in the truest sense which I must say is a rarity. The events were exhausting but very rewarding at the same time. As hectic as the three city trip was I tried to see at least some of the major sights (mostly at night) since this was my very first time to India. I think the slideshow below is a good representation of the riddle wrapped up in an enigma that is India (and the rest of the Indian sub-continent for that matter): Ironically enough what struck me the most during this trip is the woman pictured below - Shushma. My chauffeur, tour guide and friend for a day, she fluidly navigated the madness that is Mumbai traffic with skills that would make Evel Knievel blush while simultaneously pointing out sights and prompting me to take pictures (Mumbai was my stopover and gateway to/from India). In some ways she is probably the most potent symbol of the new India. When we parted ways I told her she should take solace in the fact she has won mostly without a fight a potentially hazardous battle her sisters across the Arabian sea are still fighting. I'm not sure she entirely understood the significance of what I told her. I hope that she did. I also had occasion to take a pretty cool local bus ride from Chennai to Bangalore instead of yet another boring flight. All in all I really enjoyed the trip to India and hope to return again soon. Jai Hind :-)!

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• TiVo Follow-up&hellip;Training Opportunities

  - by MightyZot

  A few posts ago I talked about my experience with TiVo Customer Service. While I didn’t receive bad service per se, I felt like the reps could have communicated better. I made the argument that it should be just as easy to leave a company as it is to engage with a company, even though my intention is to remain a TiVo fan. I worked for DataStorm Technologies in the early 90s. I pointed out to another developer that we were leaving files behind in our installations. My opinion was that, if the customer is uninstalling our application, there should be no trace of it left after uninstall except for the customer’s data. He replied with, “screw ‘em. They’re leaving us. Why do we care if we left anything behind?” Wow. Surely there is a lot of arrogance in that statement. Think about this…how often do you change your services, devices, or whatever?  Personally, I change things up about once every two or three years. If I don’t change things up, I at least think about it. So, every two or three years there is an opportunity for you (as a vendor or business) to sell me something. (That opportunity actually exists all the time, because there are many of these two or three year periods overlapping.) Likewise, you have the opportunity to win back my business every two or three years as well. Customer service on exit is just as important as customer service during engagement because, every so often, you have another chance to gain back my loyalty. If you screw that up on exit, your chances are close to zero. In addition, you need to consider all of the potential or existing customers that are part of or affected by my social organizations. “Melissa” at TiVo gave me a call last week and set up some time to talk about my experience. We talked yesterday and she gave me a few moments to pontificate about my thoughts on the importance of a complete customer experience. She had listened to my customer support calls and agreed that I had made it clear that I intended to remain a TiVo customer even though suddenLink is handling my subscription. She said that suddenLink is a very important partner for them and, of course, they want to do everything they can to support TiVo / suddenLink customers.  “Melissa” also said that they had turned this experience into a training opportunity for the reps involved. I hope that is true, because that “programmer arrogance” that I mentioned above (which was somewhat pervasive back then) may be part of the reason why that company is no longer around. Good job “Melissa”!  And, like I said, I am still a TiVo fan. In fact, we love our new TiVo and many of the great new features. In addition, if you’re one of the two people that read these posts, please remember that these are just opinions. Your experiences may be, and likely will be, completely unique to you.

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• Solving Euler Project Problem Number 1 with Microsoft Axum

  - by Jeff Ferguson

  Note: The code below applies to version 0.3 of Microsoft Axum. If you are not using this version of Axum, then your code may differ from that shown here. I have just solved Problem 1 of Project Euler using Microsoft Axum. The problem statement is as follows: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. My Axum-based solution is as follows: namespace EulerProjectProblem1{ // http://projecteuler.net/index.php?section=problems&id=1 // // If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. // The sum of these multiples is 23. // Find the sum of all the multiples of 3 or 5 below 1000. channel SumOfMultiples { input int Multiple1; input int Multiple2; input int UpperBound; output int Sum; } agent SumOfMultiplesAgent : channel SumOfMultiples { public SumOfMultiplesAgent() { int Multiple1 = receive(PrimaryChannel::Multiple1); int Multiple2 = receive(PrimaryChannel::Multiple2); int UpperBound = receive(PrimaryChannel::UpperBound); int Sum = 0; for(int Index = 1; Index < UpperBound; Index++) { if((Index % Multiple1 == 0) || (Index % Multiple2 == 0)) Sum += Index; } PrimaryChannel::Sum <-- Sum; } } agent MainAgent : channel Microsoft.Axum.Application { public MainAgent() { var SumOfMultiples = SumOfMultiplesAgent.CreateInNewDomain(); SumOfMultiples::Multiple1 <-- 3; SumOfMultiples::Multiple2 <-- 5; SumOfMultiples::UpperBound <-- 1000; var Sum = receive(SumOfMultiples::Sum); System.Console.WriteLine(Sum); System.Console.ReadLine(); PrimaryChannel::ExitCode <-- 0; } }} Let’s take a look at the various parts of the code. I begin by setting up a channel called SumOfMultiples that accepts three inputs and one output. The first two of the three inputs will represent the two possible multiples, which are three and five in this case. The third input will represent the upper bound of the problem scope, which is 1000 in this case. The lone output of the channel represents the sum of all of the matching multiples: channel SumOfMultiples{ input int Multiple1; input int Multiple2; input int UpperBound; output int Sum;} I then set up an agent that uses the channel. The agent, called SumOfMultiplesAgent, received the three inputs from the channel sent to the agent, stores the results in local variables, and performs the for loop that iterates from 1 to the received upper bound. The agent keeps track of the sum in a local variable and stores the sum in the output portion of the channel: agent SumOfMultiplesAgent : channel SumOfMultiples{ public SumOfMultiplesAgent() { int Multiple1 = receive(PrimaryChannel::Multiple1); int Multiple2 = receive(PrimaryChannel::Multiple2); int UpperBound = receive(PrimaryChannel::UpperBound); int Sum = 0; for(int Index = 1; Index < UpperBound; Index++) { if((Index % Multiple1 == 0) || (Index % Multiple2 == 0)) Sum += Index; } PrimaryChannel::Sum <-- Sum; }} The application’s main agent, therefore, simply creates a new SumOfMultiplesAgent in a new domain, prepares the channel with the inputs that we need, and then receives the Sum from the output portion of the channel: agent MainAgent : channel Microsoft.Axum.Application{ public MainAgent() { var SumOfMultiples = SumOfMultiplesAgent.CreateInNewDomain(); SumOfMultiples::Multiple1 <-- 3; SumOfMultiples::Multiple2 <-- 5; SumOfMultiples::UpperBound <-- 1000; var Sum = receive(SumOfMultiples::Sum); System.Console.WriteLine(Sum); System.Console.ReadLine(); PrimaryChannel::ExitCode <-- 0; }} The result of the calculation (which, by the way, is 233,168) is sent to the console using good ol’ Console.WriteLine().

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• How does the Trash Can work, and where can I find official documentation, reference, or specification for it?

  - by MestreLion

  When trying to manage trash can from mounted NTFS volumes, I ended up reading FreeDesktop.org's reference on it. Poking around and doing some tests, I realized Ubuntu/Gnome does not follow the specs 100%. Here's why: For non-/ partitions, it always uses <driveroot>/.Trash-<uid>, It never used <driveroot>/.Trash/<uid>, even when i created it in advance. While this works, it's annoying: if I have 15 users, I end up with 15 /.Trash-xxx folders in my drive, while the other approach would still give a single folder (with 15 sub-folders). That "pollution" in my drives is very unpleasant. And specs say "If an $topdir/.Trash directory is absent, an $topdir/.Trash-$uid directory is to be used". Well, it IS present, so why does it never use it? root trash does not work, at least not out of the box. Open nautilus as root and click on trash; it gives an error. Try to delete any file, it says "it can't move to trash". Ok, I know this can be fixed by creating /root/.local/share. But specs says "A “home trash” directory SHOULD be automatically created for any new user. If this directory is needed for a trashing operation but does not exist, the implementation SHOULD automatically create it, without any warnings or delays.". Why the error then? Bug? Why must I change /etc/fstab entries for mounted volumes, adding options like uid and guid, if the volumes are already mounted as RW for everyone? These are just some examples of deviation from the standard. So, the question is: "If Ubuntu does not adhere 100% to the spec, HOW exactly does the trash work? WHERE can i find a technical reference for Ubuntu's implementation of the trash?" By the way: if Ubuntu does happen to follow specs, please tell me what I am doing wrong, especially regarding the /.Trash-<uid> vs /.Trash/<uid> issue. Thanks! EDIT: Some more info: If a given fs has no support for the sticky bit (VFAT, NTFS), it probably doesn't have for permissions either (at least VFAT surely doesn't). So what prevents one user from purging / restoring other users' ./Trash-xxx ? If one can read/write his own Trash, one can do the same for the whole drive, including other's trashes, correct? Or does Gnome have some kind of "extra" protection on ./Trash-xxx folders on VFAT/NTFS fs? If Linux can "emulate" file permissions on NTFS mounting by editing /fstab uid and gid options, can it also "emulate" the sticky bit? I would really prefer to use /.Trash/xxx format... For the root issue: for the / partition, I can use trash as root, and it goes to /root/.local/shate/Trash. But if I click on Nautilus "Trash" (as root), I get an error. Don't you? So files are correctly trashed, but I can't access it. All I can do is manually "purge" them (by deleting files on /root/.local/shate/Trash), but restoring would be very tricky (opening info files and manually moving, etc.). For non-/ partitions (or at least for VFAT/NTFS), I can not even use trash as root: it does not create a ./Trash-0 folder, it simply says "Cannot trash, want to permanently delete?" Why? About fstab: i use it for a permanent mount for my NTFS partitions. I have several, and if not "pre-mounted" they really clutter the desktop and/or Nautilus. I'd rather have it pre-mounted, integrated in my fs, in mounts like /data , /windows/xp , /windows/vista , and so on, and leave /media and its "mount/unmount" flexibility just for truly removable drives. So, if Ubuntu/Gnome truly follows the spec, is there any way to fix the root issues and to "emulate" the sticky bit for (at least) my fstab'ed NTFS fixed partitions?

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• SQL Azure: Notes on Building a Shard Technology

  - by Herve Roggero

  In Chapter 10 of the book on SQL Azure (http://www.apress.com/book/view/9781430229612) I am co-authoring, I am digging deeper in what it takes to write a Shard. It's actually a pretty cool exercise, and I wanted to share some thoughts on how I am designing the technology. A Shard is a technology that spreads the load of database requests over multiple databases, as transparently as possible. The type of shard I am building is called a Vertical Partition Shard  (VPS). A VPS is a mechanism by which the data is stored in one or more databases behind the scenes, but your code has no idea at design time which data is in which database. It's like having a mini cloud for records instead of services. Imagine you have three SQL Azure databases that have the same schema (DB1, DB2 and DB3), you would like to issue a SELECT * FROM Users on all three databases, concatenate the results into a single resultset, and order by last name. Imagine you want to ensure your code doesn't need to change if you add a new database to the shard (DB4). Now imagine that you want to make sure all three databases are queried at the same time, in a multi-threaded manner so your code doesn't have to wait for three database calls sequentially. Then, imagine you would like to obtain a breadcrumb (in the form of a new, virtual column) that gives you a hint as to which database a record came from, so that you could update it if needed. Now imagine all that is done through the standard SqlClient library... and you have the Shard I am currently building. Here are some lessons learned and techniques I am using with this shard: Parellel Processing: Querying databases in parallel is not too hard using the Task Parallel Library; all you need is to lock your resources when needed Deleting/Updating Data: That's not too bad either as long as you have a breadcrumb. However it becomes more difficult if you need to update a single record and you don't know in which database it is. Inserting Data: I am using a round-robin approach in which each new insert request is directed to the next database in the shard. Not sure how to deal with Bulk Loads just yet... Shard Databases:  I use a static collection of SqlConnection objects which needs to be loaded once; from there on all the Shard commands use this collection Extension Methods: In order to make it look like the Shard commands are part of the SqlClient class I use extension methods. For example I added ExecuteShardQuery and ExecuteShardNonQuery methods to SqlClient. Exceptions: Capturing exceptions in a multi-threaded code is interesting... but I kept it simple for now. I am using the ConcurrentQueue to store my exceptions. Database GUID: Every database in the shard is given a GUID, which is calculated based on the connection string's values. DataTable. The Shard methods return a DataTable object which can be bound to objects.  I will be sharing the code soon as an open-source project in CodePlex. Please stay tuned on twitter to know when it will be available (@hroggero). Or check www.bluesyntax.net for updates on the shard. Thanks!

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• How does Trash Can works? Where can i find official specification / documentation / reference about it?

  - by MestreLion

  When trying to manage trash can from mounted NTFS volumes, I ended up reading FreeDesktop.org's reference on it. Poking around and doing some tests, I realized Ubuntu/Gnome does not follow the specs 100%. Here's why: For non-/ partitions, it always use <driveroot>/.Trash-<uid>, It never used <driveroot>/.Trash/<uid>, even when i created it in advance. While this works, its annoying: if i have 15 users, i end up with 15 /.Trash-xxx folders in my drive, while the other approach would still give a single folder (with 15 sub-folders). That "pollution" in my drives is very unpleasant. And specs say "If an $topdir/.Trash directory is absent, an $topdir/.Trash-$uid directory is to be used". Well, it IS present, so why it never uses it? root trash does not work, at least not out of the box. Open nautilus as root and click on trash, it gives error. Try to delete any file, it says "it cant move to trash". Ok, i know this can be fixed by creating /root/.local/share. But specs says "A “home trash” directory SHOULD be automatically created for any new user. If this directory is needed for a trashing operation but does not exist, the implementation SHOULD automatically create it, without any warnings or delays.". Why error then? Bug? Why do i must change /etc/fstab entries for mounted volumes, adding options like uid and guid, if the volumes are already mounted as RW for everyone? These are just some examples of deviation from standard. So, the question is: "If Ubuntu does not adhere 100% to the spec, HOW exactly does the trash work? WHERE can i find technical reference about Ubuntu's implementation of the trash?" By the way: if Ubuntu does happen to follow specs, please tell me what am i doing wrong, specially regarding the /.Trash-<uid> vs /.Trash/<uid> issue. Thanks! EDIT: Some more info: If a given fs has no support for sticky bit (VFAT, NTFS), it probably dont have for permitions either (at least VFAT surely doesnt). So what prevents one user for purging / restoring other users ./Trash-xxx ? If one can read/write his own Trash, he can also do the same for the whole drive, including other's trashes, isnt it? Or does Gnome has any "extra" protection on ./Trash-xxx folders on VFAT/NTFS fs? If Linux can "emulate" file permitions on NTFS mounting by editing /fstab uid and gid options, can it also "emulate" the sticky bit? I would really want to use /.Trash/xxx format... For the root issue: for the / partition, i can trash as root, and it goes to /root/.local/shate/Trash. But if i click on Nautilus "Trash" (as root), i get an error. Dont you? So files are correctly trashed, but i cant access it. All i can do is manually "purge" them (by deleting files on /root/.local/shate/Trash), but restoring would be very tricky (opening info files and manually moving, etc) For non-/ partitions (or at least for VFAT/NTFS), I can not even trash as root: it does not create a ./Trash-0 folder, it simply says "Cannot trash, want to permantly delete?" Why? About fstab: i use it for a permanent mount for my NTFS partitions. I have several, and if not "pre-mounted" they really cluttter desktop and/or Nautilus. Id rather have it pre mounted, integrated in my fs, in mounts like /data , /windows/xp , /windows/vista , and so on, and leave /media and its "mount/unmount" flexibility just for truly removable drives Si, if Ubuntu/Gnome truly follow the spec, is there any way to fix the root issues and to "emulate" the sticky bit for (at least) my fstab'ed NTFS fixed partitions?

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• Why do I need two Instances in Windows Azure?

  - by BuckWoody

  Windows Azure as a Platform as a Service (PaaS) means that there are various components you can use in it to solve a problem: Compute “Roles” - Computers running an OS and optionally IIS - you can have more than one "Instance" of a given Role Storage - Blobs, Tables and Queues for Storage Other Services - Things like the Service Bus, Azure Connection Services, SQL Azure and Caching It’s important to understand that some of these services are Stateless and others maintain State. Stateless means (at least in this case) that a system might disappear from one physical location and appear elsewhere. You can think of this as a cashier at the front of a store. If you’re in line, a cashier might take his break, and another person might replace him. As long as the order proceeds, you as the customer aren’t really affected except for the few seconds it takes to change them out. The cashier function in this example is stateless. The Compute Role Instances in Windows Azure are Stateless. To upgrade hardware, because of a fault or many other reasons, a Compute Role's Instance might stop on one physical server, and another will pick it up. This is done through the controlling fabric that Windows Azure uses to manage the systems. It’s important to note that storage in Azure does maintain State. Your data will not simply disappear - it is maintained - in fact, it’s maintained three times in a single datacenter and all those copies are replicated to another for safety. Going back to our example, storage is similar to the cash register itself. Even though a cashier leaves, the record of your payment is maintained. So if a Compute Role Instance can disappear and re-appear, the things running on that first Instance would stop working. If you wrote your code in a Stateless way, then another Role Instance simply re-starts that transaction and keeps working, just like the other cashier in the example. But if you only have one Instance of a Role, then when the Role Instance is re-started, or when you need to upgrade your own code, you can face downtime, since there’s only one. That means you should deploy at least two of each Role Instance not only for scale to handle load, but so that the first “cashier” has someone to replace them when they disappear. It’s not just a good idea - to gain the Service Level Agreement (SLA) for our uptime in Azure it’s a requirement. We point this out right in the Management Portal when you deploy the application: (Click to enlarge) When you deploy a Role Instance you can also set the “Upgrade Domain”. Placing Roles on separate Upgrade Domains means that you have a continuous service whenever you upgrade (more on upgrades in another post) - the process looks like this for two Roles. This example covers the scenario for upgrade, so you have four roles total - One Web and one Worker running the "older" code, and one of each running the new code. In all those Roles you want at least two instances, and this example shows that you're covered for High Availability and upgrade paths: The take-away is this - always plan for forward-facing Roles to have at least two copies. For Worker Roles that do background processing, there are ways to architect around this number, but it does affect the SLA if you have only one.

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• The best computer ever

  - by Jeff

  (This is a repost from my personal blog… wow… I need to write more technical stuff!) About three years and three months ago, I bought a 17" MacBook Pro, and it turned out to be the best computer I've ever owned. You might think that every computer with better specs is automatically better than the last, but that hasn't been my experience. My first one was a Sony, back in the Pentium III days, and it cost an astonishing $2,500. That was even more ridiculous in 1999 dollars. It had a dial-up modem, and a CD-ROM, built-in! It may have even played DVD's. A few years later I bought an HP, and it ended up being a pile of shit. The power connector inside came loose from the board, and on occasion would even short. In 2005, I bought a Dell, and it wasn't bad. It had a really high resolution screen (complete with dead pixels, a problem in those days), and it was the first laptop I felt I could do real work on. When 2006 rolled around, Apple started making computers with Intel CPU's, and I bought the very first one the week it came out. I used Boot Camp to run Windows. I still have it in its box somewhere, and I used it for three years. The current 17" was new in 2009. The goodness was largely rooted in having a big screen with lots of dots. This computer has been the source of hundreds of blog posts, tens of thousands of lines of code, video and photo editing, and of course, a whole lot of Web surfing. It connected to corpnet at Microsoft, WiFi in Hawaii and has presented many a deck. It has traveled with me tens of thousands of miles. Last year, I put a solid state drive in it, and it was like getting a new computer. I can boot up a Windows 7 VM in about 19 seconds. Having 8 gigs of RAM has always been fantastic. Everything about it has been fast and fun. When new, the battery (when not using VM's) could get as much as 10 hours. I can still do 7 without much trouble. After 460 charge cycles, the battery health is still between 85 and 90%. The only real negative has been the size and weight. It's only an inch thick, but naturally it's pretty big with a 17" screen. You don't get battery life like that without a huge battery, either, so it's heavy. It was never a deal breaker, but sometimes a long haul across a large airport, you know you're carrying it. Today, Apple announced a new, thinner and lighter 15" laptop, with twice the RAM and CPU cores, and four times the screen resolution. It basically handles my size and weight issues while retaining the resolution, and it still costs less than my 17" did. So I ordered one. Three years is an excellent run, but I kind of budgeted for a new workhorse this year anyway. So if you're interested in a 17" MacBook Pro with a Core 2 Duo 2.66 GHz CPU, 8 gigs of RAM and a 320 gig hard drive (sorry, I'm keeping the SSD), I have one to sell. They've apparently discontinued the 17", which is going to piss off the video community. It's in excellent condition, with a few minor scratches, but I take care of my stuff.

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