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• Waterfall Model (SDLC) vs. Prototyping Model

  The characters in the fable of the Tortoise and the Hare can easily be used to demonstrate the similarities and differences between the Waterfall and Prototyping software development models. This children fable is about a race between a consistently slow moving but steadfast turtle and an extremely fast but unreliable rabbit. After closely comparing each character’s attributes in correlation with both software development models, a trend seems to appear in that the Waterfall closely resembles the Tortoise in that Waterfall Model is typically a slow moving process that is broken up in to multiple sequential steps that must be executed in a standard linear pattern. The Tortoise can be quoted several times in the story saying “Slow and steady wins the race.” This is the perfect mantra for the Waterfall Model in that this model is seen as a cumbersome and slow moving. Waterfall Model Phases Requirement Analysis & Definition This phase focuses on defining requirements for a project that is to be developed and determining if the project is even feasible. Requirements are collected by analyzing existing systems and functionality in correlation with the needs of the business and the desires of the end users. The desired output for this phase is a list of specific requirements from the business that are to be designed and implemented in the subsequent steps. In addition this phase is used to determine if any value will be gained by completing the project. System Design This phase focuses primarily on the actual architectural design of a system, and how it will interact within itself and with other existing applications. Projects at this level should be viewed at a high level so that actual implementation details are decided in the implementation phase. However major environmental decision like hardware and platform decision are typically decided in this phase. Furthermore the basic goal of this phase is to design an application at the system level in those classes, interfaces, and interactions are defined. Additionally decisions about scalability, distribution and reliability should also be considered for all decisions. The desired output for this phase is a functional  design document that states all of the architectural decisions that have been made in regards to the project as well as a diagrams like a sequence and class diagrams. Software Design This phase focuses primarily on the refining of the decisions found in the functional design document. Classes and interfaces are further broken down in to logical modules based on the interfaces and interactions previously indicated. The output of this phase is a formal design document. Implementation / Coding This phase focuses primarily on implementing the previously defined modules in to units of code. These units are developed independently are intergraded as the system is put together as part of a whole system. Software Integration & Verification This phase primarily focuses on testing each of the units of code developed as well as testing the system as a whole. There are basic types of testing at this phase and they include: Unit Test and Integration Test. Unit Test are built to test the functionality of a code unit to ensure that it preforms its desired task. Integration testing test the system as a whole because it focuses on results of combining specific units of code and validating it against expected results. The output of this phase is a test plan that includes test with expected results and actual results. System Verification This phase primarily focuses on testing the system as a whole in regards to the list of project requirements and desired operating environment. Operation & Maintenance his phase primarily focuses on handing off the competed project over to the customer so that they can verify that all of their requirements have been met based on their original requirements. This phase will also validate the correctness of their requirements and if any changed need to be made. In addition, any problems not resolved in the previous phase will be handled in this section. The Waterfall Model’s linear and sequential methodology does offer a project certain advantages and disadvantages. Advantages of the Waterfall Model Simplistic to implement and execute for projects and/or company wide Limited demand on resources Large emphasis on documentation Disadvantages of the Waterfall Model Completed phases cannot be revisited regardless if issues arise within a project Accurate requirement are never gather prior to the completion of the requirement phase due to the lack of clarification in regards to client’s desires. Small changes or errors that arise in applications may cause additional problems The client cannot change any requirements once the requirements phase has been completed leaving them no options for changes as they see their requirements changes as the customers desires change. Excess documentation Phases are cumbersome and slow moving Learn more about the Major Process in the Sofware Development Life Cycle and Waterfall Model. Conversely, the Hare shares similar traits with the prototyping software development model in that ideas are rapidly converted to basic working examples and subsequent changes are made to quickly align the project with customers desires as they are formulated and as software strays from the customers vision. The basic concept of prototyping is to eliminate the use of well-defined project requirements. Projects are allowed to grow as the customer needs and request grow. Projects are initially designed according to basic requirements and are refined as requirement become more refined. This process allows customer to feel their way around the application to ensure that they are developing exactly what they want in the application This model also works well for determining the feasibility of certain approaches in regards to an application. Prototypes allow for quickly developing examples of implementing specific functionality based on certain techniques. Advantages of Prototyping Active participation from users and customers Allows customers to change their mind in specifying requirements Customers get a better understanding of the system as it is developed Earlier bug/error detection Promotes communication with customers Prototype could be used as final production Reduced time needed to develop applications compared to the Waterfall method Disadvantages of Prototyping Promotes constantly redefining project requirements that cause major system rewrites Potential for increased complexity of a system as scope of the system expands Customer could believe the prototype as the working version. Implementation compromises could increase the complexity when applying updates and or application fixes When companies trying to decide between the Waterfall model and Prototype model they need to evaluate the benefits and disadvantages for both models. Typically smaller companies or projects that have major time constraints typically head for more of a Prototype model approach because it can reduce the time needed to complete the project because there is more of a focus on building a project and less on defining requirements and scope prior to the start of a project. On the other hand, Companies with well-defined requirements and time allowed to generate proper documentation should steer towards more of a waterfall model because they are in a position to obtain clarified requirements and have to design and optimal solution prior to the start of coding on a project.

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• Pixel Shader Giving Black output

  - by Yashwinder

  I am coding in C# using Windows Forms and the SlimDX API to show the effect of a pixel shader. When I am setting the pixel shader, I am getting a black output screen but if I am not using the pixel shader then I am getting my image rendered on the screen. I have the following C# code using System; using System.Collections.Generic; using System.Linq; using System.Windows.Forms; using System.Runtime.InteropServices; using SlimDX.Direct3D9; using SlimDX; using SlimDX.Windows; using System.Drawing; using System.Threading; namespace WindowsFormsApplication1 { // Vertex structure. [StructLayout(LayoutKind.Sequential)] struct Vertex { public Vector3 Position; public float Tu; public float Tv; public static int SizeBytes { get { return Marshal.SizeOf(typeof(Vertex)); } } public static VertexFormat Format { get { return VertexFormat.Position | VertexFormat.Texture1; } } } static class Program { public static Device D3DDevice; // Direct3D device. public static VertexBuffer Vertices; // Vertex buffer object used to hold vertices. public static Texture Image; // Texture object to hold the image loaded from a file. public static int time; // Used for rotation caculations. public static float angle; // Angle of rottaion. public static Form1 Window =new Form1(); public static string filepath; static VertexShader vertexShader = null; static ConstantTable constantTable = null; static ImageInformation info; [STAThread] static void Main() { filepath = "C:\\Users\\Public\\Pictures\\Sample Pictures\\Garden.jpg"; info = new ImageInformation(); info = ImageInformation.FromFile(filepath); PresentParameters presentParams = new PresentParameters(); // Below are the required bare mininum, needed to initialize the D3D device. presentParams.BackBufferHeight = info.Height; // BackBufferHeight, set to the Window's height. presentParams.BackBufferWidth = info.Width+200; // BackBufferWidth, set to the Window's width. presentParams.Windowed =true; presentParams.DeviceWindowHandle = Window.panel2 .Handle; // DeviceWindowHandle, set to the Window's handle. // Create the device. D3DDevice = new Device(new Direct3D (), 0, DeviceType.Hardware, Window.Handle, CreateFlags.HardwareVertexProcessing, presentParams); // Create the vertex buffer and fill with the triangle vertices. (Non-indexed) // Remember 3 vetices for a triangle, 2 tris per quad = 6. Vertices = new VertexBuffer(D3DDevice, 6 * Vertex.SizeBytes, Usage.WriteOnly, VertexFormat.None, Pool.Managed); DataStream stream = Vertices.Lock(0, 0, LockFlags.None); stream.WriteRange(BuildVertexData()); Vertices.Unlock(); // Create the texture. Image = Texture.FromFile(D3DDevice,filepath ); // Turn off culling, so we see the front and back of the triangle D3DDevice.SetRenderState(RenderState.CullMode, Cull.None); // Turn off lighting D3DDevice.SetRenderState(RenderState.Lighting, false); ShaderBytecode sbcv = ShaderBytecode.CompileFromFile("C:\\Users\\yashwinder singh\\Desktop\\vertexShader.vs", "vs_main", "vs_1_1", ShaderFlags.None); constantTable = sbcv.ConstantTable; vertexShader = new VertexShader(D3DDevice, sbcv); ShaderBytecode sbc = ShaderBytecode.CompileFromFile("C:\\Users\\yashwinder singh\\Desktop\\pixelShader.txt", "ps_main", "ps_3_0", ShaderFlags.None); PixelShader ps = new PixelShader(D3DDevice, sbc); VertexDeclaration vertexDecl = new VertexDeclaration(D3DDevice, new[] { new VertexElement(0, 0, DeclarationType.Float3, DeclarationMethod.Default, DeclarationUsage.PositionTransformed, 0), new VertexElement(0, 12, DeclarationType.Float2 , DeclarationMethod.Default, DeclarationUsage.TextureCoordinate , 0), VertexElement.VertexDeclarationEnd }); Application.EnableVisualStyles(); MessagePump.Run(Window, () => { // Clear the backbuffer to a black color. D3DDevice.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.Black, 1.0f, 0); // Begin the scene. D3DDevice.BeginScene(); // Setup the world, view and projection matrices. //D3DDevice.VertexShader = vertexShader; //D3DDevice.PixelShader = ps; // Render the vertex buffer. D3DDevice.SetStreamSource(0, Vertices, 0, Vertex.SizeBytes); D3DDevice.VertexFormat = Vertex.Format; // Setup our texture. Using Textures introduces the texture stage states, // which govern how Textures get blended together (in the case of multiple // Textures) and lighting information. D3DDevice.SetTexture(0, Image); // Now drawing 2 triangles, for a quad. D3DDevice.DrawPrimitives(PrimitiveType.TriangleList , 0, 2); // End the scene. D3DDevice.EndScene(); // Present the backbuffer contents to the screen. D3DDevice.Present(); }); if (Image != null) Image.Dispose(); if (Vertices != null) Vertices.Dispose(); if (D3DDevice != null) D3DDevice.Dispose(); } private static Vertex[] BuildVertexData() { Vertex[] vertexData = new Vertex[6]; vertexData[0].Position = new Vector3(-1.0f, 1.0f, 0.0f); vertexData[0].Tu = 0.0f; vertexData[0].Tv = 0.0f; vertexData[1].Position = new Vector3(-1.0f, -1.0f, 0.0f); vertexData[1].Tu = 0.0f; vertexData[1].Tv = 1.0f; vertexData[2].Position = new Vector3(1.0f, 1.0f, 0.0f); vertexData[2].Tu = 1.0f; vertexData[2].Tv = 0.0f; vertexData[3].Position = new Vector3(-1.0f, -1.0f, 0.0f); vertexData[3].Tu = 0.0f; vertexData[3].Tv = 1.0f; vertexData[4].Position = new Vector3(1.0f, -1.0f, 0.0f); vertexData[4].Tu = 1.0f; vertexData[4].Tv = 1.0f; vertexData[5].Position = new Vector3(1.0f, 1.0f, 0.0f); vertexData[5].Tu = 1.0f; vertexData[5].Tv = 0.0f; return vertexData; } } } And my pixel shader and vertex shader code are as following // Pixel shader input structure struct PS_INPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Pixel shader output structure struct PS_OUTPUT { float4 Color : COLOR0; }; // Global variables sampler2D Tex0; // Name: Simple Pixel Shader // Type: Pixel shader // Desc: Fetch texture and blend with constant color // PS_OUTPUT ps_main( in PS_INPUT In ) { PS_OUTPUT Out; //create an output pixel Out.Color = tex2D(Tex0, In.Texture); //do a texture lookup Out.Color *= float4(0.9f, 0.8f, 0.0f, 1); //do a simple effect return Out; //return output pixel } // Vertex shader input structure struct VS_INPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Vertex shader output structure struct VS_OUTPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Global variables float4x4 WorldViewProj; // Name: Simple Vertex Shader // Type: Vertex shader // Desc: Vertex transformation and texture coord pass-through // VS_OUTPUT vs_main( in VS_INPUT In ) { VS_OUTPUT Out; //create an output vertex Out.Position = mul(In.Position, WorldViewProj); //apply vertex transformation Out.Texture = In.Texture; //copy original texcoords return Out; //return output vertex }

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• PASS: Election Changes for 2011

  - by Bill Graziano

  Last year after the election, the PASS Board created an Election Review Committee.  This group was charged with reviewing our election procedures and making suggestions to improve the process.  You can read about the formation of the group and review some of the intermediate work on the site – especially in the forums. I was one of the members of the group along with Joe Webb (Chair), Lori Edwards, Brian Kelley, Wendy Pastrick, Andy Warren and Allen White.  This group worked from October to April on our election process.  Along the way we: Interviewed interested parties including former NomCom members, Board candidates and anyone else that came forward. Held a session at the Summit to allow interested parties to discuss the issues Had numerous conference calls and worked through the various topics I can’t thank these people enough for the work they did.  They invested a tremendous number of hours thinking, talking and writing about our elections.  I’m proud to say I was a member of this group and thoroughly enjoyed working with everyone (even if I did finally get tired of all the calls.) The ERC delivered their recommendations to the PASS Board prior to our May Board meeting.  We reviewed those and made a few modifications.  I took their recommendations and rewrote them as procedures while incorporating those changes.  Their original recommendations as well as our final document are posted at the ERC documents page.  Please take a second and read them BEFORE we start the elections.  If you have any questions please post them in the forums on the ERC site. (My final document includes a change log at the end that I decided to leave in.  If you want to know which areas to pay special attention to that’s a good start.) Many of those recommendations were already posted in the forums or in the blogs of individual ERC members.  Hopefully nothing in the ERC document is too surprising. In this post I’m going to walk through some of the key changes and talk about what I remember from both ERC and Board discussions.  I’ll pay a little extra attention to things the Board changed from the ERC.  I’d also encourage any of the Board or ERC members to blog their thoughts on this. The Nominating Committee will continue to exist.  Personally, I was curious to see what the non-Board ERC members would think about the NomCom.  There was broad agreement that a group to vet candidates had value to the organization. The NomCom will be composed of five members.  Two will be Board members and three will be from the membership at large.  The only requirement for the three community members is that you’ve volunteered in some way (and volunteering is defined very broadly).  We expect potential at-large NomCom members to participate in a forum on the PASS site to answer questions from the other PASS members. We’re going to hold an election to determine the three community members.  It will be closer to voting for Summit sessions than voting for Board members.  That means there won’t be multiple dedicated emails.  If you’re at all paying attention it will be easy to participate.  Personally I wanted it easy for those that cared to participate but not overwhelm those that didn’t care.  I think this strikes a good balance. There’s also a clause that in order to be considered a winner in this NomCom election, you must receive 10 votes.  This is something I suggested.  I have no idea how popular the NomCom election is going to be.  I just wanted a fallback that if no one participated and some random person got in with one or two votes.  Any open slots will be filled by the NomCom chair (usually the PASS Immediate Past President).  My assumption is that they would probably take the next highest vote getters unless they were throwing flames in the forums or clearly unqualified.  As a final check, the Board still approves the final NomCom. The NomCom is going to rank candidates instead of rating them.  This has interesting implications.  This was championed by another ERC member and I’m hoping they write something about it.  This will really force the NomCom to make decisions between candidates.  You can’t just rate everyone a 3 and be done with it.  It may also make candidates appear further apart than they actually are.  I’m looking forward talking with the NomCom after this election and getting their feedback on this. The PASS Board added an option to remove a candidate with a unanimous vote of the NomCom.  This was primarily put in place to handle people that lied on their application or had a criminal background or some other unusual situation and we figured it out. We list an explicit goal of three candidate per open slot. We also wanted an easy way to find the NomCom candidate rankings from the ballot.  Hopefully this will satisfy those that want a broad candidate pool and those that want the NomCom to identify the most qualified candidates. The primary spokesperson for the NomCom is the committee chair.  After the issues around the election last year we didn’t have a good communication plan in place.  We should have and that was a failure on the part of the Board.  If there is criticism of the election this year I hope that falls squarely on the Board.  The community members of the NomCom shouldn’t be fielding complaints over the election process.  That said, the NomCom is ranking candidates and we are forcing them to rank some lower than others.  I’m sure you’ll each find someone that you think should have been ranked differently.  I also want to highlight one other change to the process that we started last year and isn’t included in these documents.  I think the candidate forums on the PASS site were tremendously helpful last year in helping people to find out more about candidates.  That gives our members a way to ask hard questions of the candidates and publicly see their answers. This year we have two important groups to fill.  The first is the NomCom.  We need three people from our membership to step up and fill this role.  It won’t be easy.  You will have to make subjective rankings of your fellow community members.  Your actions will be important in deciding who the future leaders of PASS will be.  There’s a 50/50 chance that one of the people you interview will be the President of PASS someday.  This is not a responsibility to be taken lightly. The second is the slate of candidates.  If you’ve ever thought about running for the Board this is the year.  We’ve never had nine candidates on the ballot before.  Your chance of making it through the NomCom are higher than in any previous year.  Unfortunately the more of you that run, the more of you that will lose in the election.  And hopefully that competition will mean more community involvement and better Board members for PASS. Is this the end of changes to the election process?  It isn’t.  Every year that I’ve been on the Board the election process has changed.  Some years there have been small changes and some years there have been large changes.  After this election we’ll look at how the process worked and decide what steps to take – just like we do every year.

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• Create and Backup Multiple Profiles in Google Chrome

  - by Asian Angel

  Other browsers such as Firefox and SeaMonkey allow you to have multiple profiles but not Chrome…at least not until now. If you want to use multiple profiles and create backups for them then join us as we look at Google Chrome Backup. Note: There is a paid version of this program available but we used the free version for our article. Google Chrome Backup in Action During the installation process you will run across this particular window. It will have a default user name filled in as shown here…you will not need to do anything except click on Next to continue installing the program. When you start the program for the first time this is what you will see. Your default Chrome Profile will already be visible in the window. A quick look at the Profile Menu… In the Tools Menu you can go ahead and disable the Start program at Windows Startup setting…the only time that you will need the program running is if you are creating or restoring a profile. When you create a new profile the process will start with this window. You can access an Advanced Options mode if desired but most likely you will not need it. Here is a look at the Advanced Options mode. It is mainly focused on adding Switches to the new Chrome Shortcut. The drop-down menu for the Switches available… To create your new profile you will need to choose: A profile location A profile name (as you type/create the profile name it will automatically be added to the Profile Path) Make certain that the Create a new shortcut to access new profile option is checked For our example we decided to try out the Disable plugins switch option… Click OK to create the new profile. Once you have created your new profile, you will find a new shortcut on the Desktop. Notice that the shortcut’s name will be Google Chrome + profile name that you chose. Note: On our system we were able to move the new shortcut to the “Start Menu” without problems. Clicking on our new profile’s shortcut opened up a fresh and clean looking instance of Chrome. Just out of curiosity we did decide to check the shortcut to see if the Switch set up correctly. Unfortunately it did not in this instance…so your mileage with the Switches may vary. This was just a minor quirk and nothing to get excited or upset over…especially considering that you can create multiple profiles so easily. After opening up our default profile of Chrome you can see the individual profile icons (New & Default in order) sitting in the Taskbar side-by-side. And our two profiles open at the same time on our Desktop… Backing Profiles Up For the next part of our tests we decided to create a backup for each of our profiles. Starting the wizard will allow you to choose between creating or restoring a profile. Note: To create or restore a backup click on Run Wizard. When you reach the second part of the process you can go with the Backup default profile option or choose a particular one from a drop-down list using the Select a profile to backup option. We chose to backup the Default Profile first… In the third part of the process you will need to select a location to save the profile to. Once you have selected the location you will see the Target Path as shown here. You can choose your own name for the backup file…we decided to go with the default name instead since it contained the backup’s calendar date. A very nice feature is the ability to have the cache cleared before creating the backup. We clicked on Yes…choose the option that best suits your needs. Once you have chosen either Yes or No the backup will then be created. Click Finish to complete the process. The backup file for our Default Profile at 14.0 MB in size. And the backup file for our Chrome Fresh Profile…2.81 MB. Restoring Profiles For the final part of our tests we decided to do a Restore. Select Restore and click Next to get the process started. In the second step you will need to browse for the Profile Backup File (and select the desired profile if you have created multiples). For our example we decided to overwrite the original Default Profile with the Chrome Fresh Profile. The third step lets you choose where to restore the chosen profile to…you can go with the Default Profile or choose one from the drop-down list using the Restore to a selected profile option. The final step will get you on your way to restoring the chosen profile. The program will conduct a check regarding the previous/old profile and ask if you would like to proceed with overwriting it. Definitely nice in case you change your mind at the last moment. Clicking Yes will finish the restoration. The only other odd quirk that we noticed while using the program was that the Next Button did not function after restoring the profile. You can easily get around the problem by clicking to close the window. Which one is which? After the restore process we had identical twins. Conclusion If you have been looking for a way to create multiple profiles in Google Chrome, then you might want to add this program to your system. Links Download Google Chrome Backup Similar Articles Productive Geek Tips Backup and Restore Firefox Profiles EasilyBackup Different Browsers Easily with FavBackupBackup Your Browser with the New FavBackupStupid Geek Tricks: Compare Your Browser’s Memory Usage with Google ChromeHow to Make Google Chrome Your Default Browser 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 Tech Fanboys Field Guide Check these Awesome Chrome Add-ons iFixit Offers Gadget Repair Manuals Online Vista style sidebar for Windows 7 Create Nice Charts With These Web Based Tools Track Daily Goals With 42Goals

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• Agile Testing Days 2012 – Day 3 – Agile or agile?

  - by Chris George

  Another early start for my last Lean Coffee of the conference, and again it was not wasted. We had some really interesting discussions around how to determine what test automation is useful, if agile is not faster, why do it? and a rather existential discussion on whether unicorns exist! First keynote of the day was entitled “Fast Feedback Teams” by Ola Ellnestam. Again this relates nicely to the releasing faster talk on day 2, and something that we are looking at and some teams are actively trying. Introducing the notion of feedback, Ola describes a game he wrote for his eldest child. It was a simple game where every time he clicked a button, it displayed “You’ve Won!”. He then changed it to be a Win-Lose-Win-Lose pattern and watched the feedback from his son who then twigged the pattern and got his younger brother to play, alternating turns… genius! (must do that with my children). The idea behind this was that you need that feedback loop to learn and progress. If you are not getting the feedback you need to close that loop. An interesting point Ola made was to solve problems BEFORE writing software. It may be that you don’t have to write anything at all, perhaps it’s a communication/training issue? Perhaps the problem can be solved another way. Writing software, although it’s the business we are in, is expensive, and this should be taken into account. He again mentions frequent releases, and how they should be made as soon as stuff is ready to be released, don’t leave stuff on the shelf cause it’s not earning you anything, money or data. I totally agree with this and it’s something that we will be aiming for moving forwards. “Exceptions, Assumptions and Ambiguity: Finding the truth behind the story” by David Evans started off very promising by making references to ‘Grim up North’ referring to the north of England. Not sure it was appreciated by most of the audience, but it made me laugh! David explained how there are always risks associated with exceptions, giving the example of a one-way road near where he lives, with an exception sign giving rights to coaches to go the wrong way. Therefore you could merrily swing around the corner of the one way road straight into a coach! David showed the danger in making assumptions with lyrical quotes from Lola by The Kinks “I’m glad I’m a man, and so is Lola” and with a picture of a toilet flush that needed instructions to operate the full and half flush. With this particular flush, you pulled the handle all the way down to half flush, and half way down to full flush! hmmm, a bit of a crappy user experience methinks! Then through a clever use of a passage from the Jabberwocky, David then went onto show how mis-translation/ambiguity is the can completely distort the original meaning of something, and this is a real enemy of software development. This was all helping to demonstrate that the term Story is often heavily overloaded in the Agile world, and should really be stripped back to what it is really for, stating a business problem, and offering a technical solution. Therefore a story could be worded as “In order to {make some improvement}, we will { do something}”. The first ‘in order to’ statement is stakeholder neutral, and states the problem through requesting an improvement to the software/process etc. The second part of the story is the verb, the doing bit. So to achieve the ‘improvement’ which is not currently true, we will do something to make this true in the future. My PM is very interested in this, and he’s observed some of the problems of overloading stories so I’m hoping between us we can use some of David’s suggestions to help clarify our stories better. The second keynote of the day (and our last) proved to be the most entertaining and exhausting of the conference for me. “The ongoing evolution of testing in agile development” by Scott Barber. I’ve never had the pleasure of seeing Scott before… OMG I would love to have even half of the energy he has! What struck me during this presentation was Scott’s explanation of how testing has become the role/job that it is (largely) today, and how this has led to the need for ‘methodologies’ to make dev and test work! The argument that we should be trying to converge the roles again is a very valid one, and one that a couple of the teams at work are actively doing with great results. Making developers as responsible for quality as testers is something that has been lost over the years, but something that we are now striving to achieve. The idea that we (testers) should be testing experts/specialists, not testing ‘union members’, supports this idea so the entire team works on all aspects of a feature/product, with the ‘specialists’ taking the lead and advising/coaching the others. This leads to better propagation of information around the team, a greater holistic understanding of the project and it allows the team to continue functioning if some of it’s members are off sick, for example. Feeling somewhat drained from Scott’s keynote (but at the same time excited that alot of the points he raised supported actions we are taking at work), I headed into my last presentation for Agile Testing Days 2012 before having to make my way to Tegel to catch the flight home. “Thinking and working agile in an unbending world” with Pete Walen was a talk I was not going to miss! Having spoken to Pete several times during the past few days, I was looking forward to hearing what he was going to say, and I was not disappointed. Pete started off by trying to separate the definitions of ‘Agile’ as in the methodology, and ‘agile’ as in the adjective by pronouncing them the ‘english’ and ‘american’ ways. So Agile pronounced (Ajyle) and agile pronounced (ajul). There was much confusion around what the hell he was talking about, although I thought it was quite clear. Agile – Software development methodology agile – Marked by ready ability to move with quick easy grace; Having a quick resourceful and adaptable character. Anyway, that aside (although it provided a few laughs during the presentation), the point was that many teams that claim to be ‘Agile’ but are not, in fact, ‘agile’ by nature. Implementing ‘Agile’ methodologies that are so prescriptive actually goes against the very nature of Agile development where a team should anticipate, adapt and explore. Pete made a valid point that very few companies intentionally put up roadblocks to impede work, so if work is being blocked/delayed, why? This is where being agile as a team pays off because the team can inspect what’s going on, explore options and adapt their processes. It is through experimentation (and that means trying and failing as well as trying and succeeding) that a team will improve and grow leading to focussing on what really needs to be done to achieve X. So, that was it, the last talk of our conference. I was gutted that we had to miss the closing keynote from Matt Heusser, as Matt was another person I had spoken too a few times during the conference, but the flight would not wait, and just as well we left when we did because the traffic was a nightmare! My Takeaway Triple from Day 3: Release often and release small – don’t leave stuff on the shelf Keep the meaning of the word ‘agile’ in mind when working in ‘Agile Look at testing as more of a skill than a role  

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• 10 tape technology features that make you go hmm.

  - by Karoly Vegh

  A week ago an Oracle/StorageTek Tape Specialist, Christian Vanden Balck, visited Vienna, and agreed to visit customers to do techtalks and update them about the technology boom going around tape. I had the privilege to attend some of his sessions and noted the information and features that took the customers by surprise and made them think. Allow me to share the top 10: I. StorageTek as a brand: StorageTek is one of he strongest names in the Tape field. The brand itself was valued so much by customers that even after Sun Microsystems acquiring StorageTek and the Oracle acquiring Sun the brand lives on with all the Oracle tapelibraries are officially branded StorageTek.See http://www.oracle.com/us/products/servers-storage/storage/tape-storage/overview/index.html II. Disk information density limitations: Disk technology struggles with information density. You haven't seen the disk sizes exploding lately, have you? That's partly because there are physical limits on a disk platter. The size is given, the number of platters is limited, they just can't grow, and are running out of physical area to write to. Now, in a T10000C tape cartridge we have over 1000m long tape. There you go, you have got your physical space and don't need to stuff all that data crammed together. You can write in a reliable pattern, and have space to grow too. III. Oracle has a market share of 62% worldwide in recording head manufacturing. That's right. If you are running LTO drives, with a good chance you rely on StorageTek production. That's two out of three LTO recording heads produced worldwide.  IV. You can store 1 Exabyte data in a single tape library. Yes, an Exabyte. That is 1000 Petabytes. Or, a million Terabytes. A thousand million GigaBytes. You can store that in a stacked StorageTek SL8500 tapelibrary. In one SL8500 you can put 10.000 T10000C cartridges, that store 10TB data (compressed). You can stack 10 of these SL8500s together. Boom. 1000.000 TB.(n.b.: stacking means interconnecting the libraries. Yes, cartridges are moved between the stacked libraries automatically.)  V. EMC: 'Tape doesn't suck after all. We moved on.': Do you remember the infamous 'Tape sucks, move on' Datadomain slogan? Of course they had to put it that way, having only had disk products. But here's a fun fact: on the EMCWorld 2012 there was a major presence of a Tape-tech company - EMC, in a sudden burst of sanity is embracing tape again. VI. The miraculous T10000C: Oracle StorageTek has developed an enterprise-grade tapedrive and cartridge, the T10000C. With awesome numbers: The Cartridge: Native 5TB capacity, 10TB with compression Over a kilometer long tape within the cartridge. And it's locked when unmounted, no rattling of your data.  Replaced the metalparticles datalayer with BaFe (bariumferrite) - metalparticles lose around 7% of magnetism within 30 days. BaFe does not. Yes we employ solid-state physicists doing R&D on demagnetisation in our labs. Can be partitioned, storage tiering within the cartridge!  The Drive: 2GB Cache Encryption implemented in HW - no performance hit 252 MB/s native sustained data rate, beats disk technology by far. Not to mention peak throughput.  Leading the tape while never touching the data side of it, protecting your data physically too Data integritiy checking (CRC recalculation) on tape within the drive without having to read it back to the server reordering data from tape-order, delivering it back in application-order  writing 32 tracks at once, reading them back for CRC check at once VII. You only use 20% of your data on a regular basis. The rest 80% is just lying around for years. On continuously spinning disks. Doubly consuming energy (power+cooling), blocking diskstorage capacity. There is a solution called SAM (Storage Archive Manager) that provides you a filesystem unifying disk and tape, moving data on-demand and for clients transparently between the different storage tiers. You can share these filesystems with NFS or CIFS for clients, and enjoy the low TCO of tape. Tapes don't spin. They sit quietly in their slots, storing 10TB data, using no energy, producing no heat, automounted when a client accesses their data.See: http://www.oracle.com/us/products/servers-storage/storage/storage-software/storage-archive-manager/overview/index.html VIII. HW supported for three decades: Did you know that the original PowderHorn library was released in '87 and has been only discontinued in 2010? That is over two decades of supported operation. Tape libraries are - just like the data carrying on tapecartridges - built for longevity. Oh, and the T10000C cartridge has 30-year archival life for long-term retention.  IX. Tape is easy to manage: Have you heard of Tape Storage Analytics? It is a central graphical tool to summarize, monitor, analyze dataflow, health and performance of drives and libraries, see: http://www.oracle.com/us/products/servers-storage/storage/tape-storage/tape-analytics/overview/index.html X. The next generation: The T10000B drives were able to reuse the T10000A cartridges and write on them even more data. On the same cartridges. We call this investment protection, and this is very important for Oracle for the future too. We usually support two generations of cartridges together. The current drive is a T10000C. (...I know I promised to enlist 10, but I got still two more I really want to mention. Allow me to work around the problem: ) X++. The TallBots, the robots moving around the cartridges in the StorageTek library from tapeslots to the drives are cableless. Cables, belts, chains running to moving parts in a library cause maintenance downtimes. So StorageTek eliminated them. The TallBots get power, commands, even firmwareupgrades through the rails they are running on. Also, the TallBots don't just hook'n'pull the tapes out of their slots, they actually grip'n'lift them out. No friction, no scratches, no zillion little plastic particles floating around in the library, in the drives, on your data. (X++)++: Tape beats SSDs and Disks. In terms of throughput (252 MB/s), in terms of TCO: disks cause around 290x more power and cooling, in terms of capacity: 10TB on a single media and soon more.  So... do you need to store large amounts of data? Are you legally bound to archive it for dozens of years? Would you benefit from automatic storage tiering? Have you got large mediachunks to be streamed at times? Have you got power and cooling issues in the growing datacenters? Do you find EMC's 180° turn of tape attitude interesting, but appreciate it at the same time? With all that, you aren't alone. The most data on this planet is stored on tape. Tape is coming. Big time.

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• Use a Fake Http Channel to Unit Test with HttpClient

  - by Steve Michelotti

  Applications get data from lots of different sources. The most common is to get data from a database or a web service. Typically, we encapsulate calls to a database in a Repository object and we create some sort of IRepository interface as an abstraction to decouple between layers and enable easier unit testing by leveraging faking and mocking. This works great for database interaction. However, when consuming a RESTful web service, this is is not always the best approach. The WCF Web APIs that are available on CodePlex (current drop is Preview 3) provide a variety of features to make building HTTP REST services more robust. When you download the latest bits, you’ll also find a new HttpClient which has been updated for .NET 4.0 as compared to the one that shipped for 3.5 in the original REST Starter Kit. The HttpClient currently provides the best API for consuming REST services on the .NET platform and the WCF Web APIs provide a number of extension methods which extend HttpClient and make it even easier to use. Let’s say you have a client application that is consuming an HTTP service – this could be Silverlight, WPF, or any UI technology but for my example I’ll use an MVC application: 1: using System; 2: using System.Net.Http; 3: using System.Web.Mvc; 4: using FakeChannelExample.Models; 5: using Microsoft.Runtime.Serialization; 6:   7: namespace FakeChannelExample.Controllers 8: { 9: public class HomeController : Controller 10: { 11: private readonly HttpClient httpClient; 12:   13: public HomeController(HttpClient httpClient) 14: { 15: this.httpClient = httpClient; 16: } 17:   18: public ActionResult Index() 19: { 20: var response = httpClient.Get("Person(1)"); 21: var person = response.Content.ReadAsDataContract<Person>(); 22:   23: this.ViewBag.Message = person.FirstName + " " + person.LastName; 24: 25: return View(); 26: } 27: } 28: } On line #20 of the code above you can see I’m performing an HTTP GET request to a Person resource exposed by an HTTP service. On line #21, I use the ReadAsDataContract() extension method provided by the WCF Web APIs to serialize to a Person object. In this example, the HttpClient is being passed into the constructor by MVC’s dependency resolver – in this case, I’m using StructureMap as an IoC and my StructureMap initialization code looks like this: 1: using StructureMap; 2: using System.Net.Http; 3:   4: namespace FakeChannelExample 5: { 6: public static class IoC 7: { 8: public static IContainer Initialize() 9: { 10: ObjectFactory.Initialize(x => 11: { 12: x.For<HttpClient>().Use(() => new HttpClient("http://localhost:31614/")); 13: }); 14: return ObjectFactory.Container; 15: } 16: } 17: } My controller code currently depends on a concrete instance of the HttpClient. Now I *could* create some sort of interface and wrap the HttpClient in this interface and use that object inside my controller instead – however, there are a few why reasons that is not desirable: For one thing, the API provided by the HttpClient provides nice features for dealing with HTTP services. I don’t really *want* these to look like C# RPC method calls – when HTTP services have REST features, I may want to inspect HTTP response headers and hypermedia contained within the message so that I can make intelligent decisions as to what to do next in my workflow (although I don’t happen to be doing these things in my example above) – this type of workflow is common in hypermedia REST scenarios. If I just encapsulate HttpClient behind some IRepository interface and make it look like a C# RPC method call, it will become difficult to take advantage of these types of things. Second, it could get pretty mind-numbing to have to create interfaces all over the place just to wrap the HttpClient. Then you’re probably going to have to hard-code HTTP knowledge into your code to formulate requests rather than just “following the links” that the hypermedia in a message might provide. Third, at first glance it might appear that we need to create an interface to facilitate unit testing, but actually it’s unnecessary. Even though the code above is dependent on a concrete type, it’s actually very easy to fake the data in a unit test. The HttpClient provides a Channel property (of type HttpMessageChannel) which allows you to create a fake message channel which can be leveraged in unit testing. In this case, what I want is to be able to write a unit test that just returns fake data. I also want this to be as re-usable as possible for my unit testing. I want to be able to write a unit test that looks like this: 1: [TestClass] 2: public class HomeControllerTest 3: { 4: [TestMethod] 5: public void Index() 6: { 7: // Arrange 8: var httpClient = new HttpClient("http://foo.com"); 9: httpClient.Channel = new FakeHttpChannel<Person>(new Person { FirstName = "Joe", LastName = "Blow" }); 10:   11: HomeController controller = new HomeController(httpClient); 12:   13: // Act 14: ViewResult result = controller.Index() as ViewResult; 15:   16: // Assert 17: Assert.AreEqual("Joe Blow", result.ViewBag.Message); 18: } 19: } Notice on line #9, I’m setting the Channel property of the HttpClient to be a fake channel. I’m also specifying the fake object that I want to be in the response on my “fake” Http request. I don’t need to rely on any mocking frameworks to do this. All I need is my FakeHttpChannel. The code to do this is not complex: 1: using System; 2: using System.IO; 3: using System.Net.Http; 4: using System.Runtime.Serialization; 5: using System.Threading; 6: using FakeChannelExample.Models; 7:   8: namespace FakeChannelExample.Tests 9: { 10: public class FakeHttpChannel<T> : HttpClientChannel 11: { 12: private T responseObject; 13:   14: public FakeHttpChannel(T responseObject) 15: { 16: this.responseObject = responseObject; 17: } 18:   19: protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) 20: { 21: return new HttpResponseMessage() 22: { 23: RequestMessage = request, 24: Content = new StreamContent(this.GetContentStream()) 25: }; 26: } 27:   28: private Stream GetContentStream() 29: { 30: var serializer = new DataContractSerializer(typeof(T)); 31: Stream stream = new MemoryStream(); 32: serializer.WriteObject(stream, this.responseObject); 33: stream.Position = 0; 34: return stream; 35: } 36: } 37: } The HttpClientChannel provides a Send() method which you can override to return any HttpResponseMessage that you want. You can see I’m using the DataContractSerializer to serialize the object and write it to a stream. That’s all you need to do. In the example above, the only thing I’ve chosen to do is to provide a way to return different response objects. But there are many more features you could add to your own re-usable FakeHttpChannel. For example, you might want to provide the ability to add HTTP headers to the message. You might want to use a different serializer other than the DataContractSerializer. You might want to provide custom hypermedia in the response as well as just an object or set HTTP response codes. This list goes on. This is the just one example of the really cool features being added to the next version of WCF to enable various HTTP scenarios. The code sample for this post can be downloaded here.

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• Why you need to learn async in .NET

  - by PSteele

  I had an opportunity to teach a quick class yesterday about what’s new in .NET 4.0.  One of the topics was the TPL (Task Parallel Library) and how it can make async programming easier.  I also stressed that this is the direction Microsoft is going with for C# 5.0 and learning the TPL will greatly benefit their understanding of the new async stuff.  We had a little time left over and I was able to show some code that uses the Async CTP to accomplish some stuff, but it wasn’t a simple demo that you could jump in to and understand so I thought I’d thrown one together and put it in a blog post. The entire solution file with all of the sample projects is located here. A Simple Example Let’s start with a super-simple example (WindowsApplication01 in the solution). I’ve got a form that displays a label and a button.  When the user clicks the button, I want to start displaying the current time for 15 seconds and then stop. What I’d like to write is this: lblTime.ForeColor = Color.Red; for (var x = 0; x < 15; x++) { lblTime.Text = DateTime.Now.ToString("HH:mm:ss"); Thread.Sleep(1000); } lblTime.ForeColor = SystemColors.ControlText; (Note that I also changed the label’s color while counting – not quite an ILM-level effect, but it adds something to the demo!) As I’m sure most of my readers are aware, you can’t write WinForms code this way.  WinForms apps, by default, only have one thread running and it’s main job is to process messages from the windows message pump (for a more thorough explanation, see my Visual Studio Magazine article on multithreading in WinForms).  If you put a Thread.Sleep in the middle of that code, your UI will be locked up and unresponsive for those 15 seconds.  Not a good UX and something that needs to be fixed.  Sure, I could throw an “Application.DoEvents()” in there, but that’s hacky. The Windows Timer Then I think, “I can solve that.  I’ll use the Windows Timer to handle the timing in the background and simply notify me when the time has changed”.  Let’s see how I could accomplish this with a Windows timer (WindowsApplication02 in the solution): public partial class Form1 : Form { private readonly Timer clockTimer; private int counter;   public Form1() { InitializeComponent(); clockTimer = new Timer {Interval = 1000}; clockTimer.Tick += UpdateLabel; }   private void UpdateLabel(object sender, EventArgs e) { lblTime.Text = DateTime.Now.ToString("HH:mm:ss"); counter++; if (counter == 15) { clockTimer.Enabled = false; lblTime.ForeColor = SystemColors.ControlText; } }   private void cmdStart_Click(object sender, EventArgs e) { lblTime.ForeColor = Color.Red; counter = 0; clockTimer.Start(); } } Holy cow – things got pretty complicated here.  I use the timer to fire off a Tick event every second.  Inside there, I can update the label.  Granted, I can’t use a simple for/loop and have to maintain a global counter for the number of iterations.  And my “end” code (when the loop is finished) is now buried inside the bottom of the Tick event (inside an “if” statement).  I do, however, get a responsive application that doesn’t hang or stop repainting while the 15 seconds are ticking away. But doesn’t .NET have something that makes background processing easier? The BackgroundWorker Next I try .NET’s BackgroundWorker component – it’s specifically designed to do processing in a background thread (leaving the UI thread free to process the windows message pump) and allows updates to be performed on the main UI thread (WindowsApplication03 in the solution): public partial class Form1 : Form { private readonly BackgroundWorker worker;   public Form1() { InitializeComponent(); worker = new BackgroundWorker {WorkerReportsProgress = true}; worker.DoWork += StartUpdating; worker.ProgressChanged += UpdateLabel; worker.RunWorkerCompleted += ResetLabelColor; }   private void StartUpdating(object sender, DoWorkEventArgs e) { var workerObject = (BackgroundWorker) sender; for (int x = 0; x < 15; x++) { workerObject.ReportProgress(0); Thread.Sleep(1000); } }   private void UpdateLabel(object sender, ProgressChangedEventArgs e) { lblTime.Text = DateTime.Now.ToString("HH:mm:ss"); }   private void ResetLabelColor(object sender, RunWorkerCompletedEventArgs e) { lblTime.ForeColor = SystemColors.ControlText; }   private void cmdStart_Click(object sender, EventArgs e) { lblTime.ForeColor = Color.Red; worker.RunWorkerAsync(); } } Well, this got a little better (I think).  At least I now have my simple for/next loop back.  Unfortunately, I’m still dealing with event handlers spread throughout my code to co-ordinate all of this stuff in the right order. Time to look into the future. The async way Using the Async CTP, I can go back to much simpler code (WindowsApplication04 in the solution): private async void cmdStart_Click(object sender, EventArgs e) { lblTime.ForeColor = Color.Red; for (var x = 0; x < 15; x++) { lblTime.Text = DateTime.Now.ToString("HH:mm:ss"); await TaskEx.Delay(1000); } lblTime.ForeColor = SystemColors.ControlText; } This code will run just like the Timer or BackgroundWorker versions – fully responsive during the updates – yet is way easier to implement.  In fact, it’s almost a line-for-line copy of the original version of this code.  All of the async plumbing is handled by the compiler and the framework.  My code goes back to representing the “what” of what I want to do, not the “how”. I urge you to download the Async CTP.  All you need is .NET 4.0 and Visual Studio 2010 sp1 – no need to set up a virtual machine with the VS2011 beta (unless, of course, you want to dive right in to the C# 5.0 stuff!).  Starting playing around with this today and see how much easier it will be in the future to write async-enabled applications.

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• I see no LOBs!

  - by Paul White

  Is it possible to see LOB (large object) logical reads from STATISTICS IO output on a table with no LOB columns? I was asked this question today by someone who had spent a good fraction of their afternoon trying to work out why this was occurring – even going so far as to re-run DBCC CHECKDB to see if any corruption had taken place.  The table in question wasn’t particularly pretty – it had grown somewhat organically over time, with new columns being added every so often as the need arose.  Nevertheless, it remained a simple structure with no LOB columns – no TEXT or IMAGE, no XML, no MAX types – nothing aside from ordinary INT, MONEY, VARCHAR, and DATETIME types.  To add to the air of mystery, not every query that ran against the table would report LOB logical reads – just sometimes – but when it did, the query often took much longer to execute. Ok, enough of the pre-amble.  I can’t reproduce the exact structure here, but the following script creates a table that will serve to demonstrate the effect: IF OBJECT_ID(N'dbo.Test', N'U') IS NOT NULL DROP TABLE dbo.Test GO CREATE TABLE dbo.Test ( row_id NUMERIC IDENTITY NOT NULL,   col01 NVARCHAR(450) NOT NULL, col02 NVARCHAR(450) NOT NULL, col03 NVARCHAR(450) NOT NULL, col04 NVARCHAR(450) NOT NULL, col05 NVARCHAR(450) NOT NULL, col06 NVARCHAR(450) NOT NULL, col07 NVARCHAR(450) NOT NULL, col08 NVARCHAR(450) NOT NULL, col09 NVARCHAR(450) NOT NULL, col10 NVARCHAR(450) NOT NULL, CONSTRAINT [PK dbo.Test row_id] PRIMARY KEY CLUSTERED (row_id) ) ; The next script loads the ten variable-length character columns with one-character strings in the first row, two-character strings in the second row, and so on down to the 450th row: WITH Numbers AS ( -- Generates numbers 1 - 450 inclusive SELECT TOP (450) n = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM master.sys.columns C1, master.sys.columns C2, master.sys.columns C3 ORDER BY n ASC ) INSERT dbo.Test WITH (TABLOCKX) SELECT REPLICATE(N'A', N.n), REPLICATE(N'B', N.n), REPLICATE(N'C', N.n), REPLICATE(N'D', N.n), REPLICATE(N'E', N.n), REPLICATE(N'F', N.n), REPLICATE(N'G', N.n), REPLICATE(N'H', N.n), REPLICATE(N'I', N.n), REPLICATE(N'J', N.n) FROM Numbers AS N ORDER BY N.n ASC ; Once those two scripts have run, the table contains 450 rows and 10 columns of data like this: Most of the time, when we query data from this table, we don’t see any LOB logical reads, for example: -- Find the maximum length of the data in -- column 5 for a range of rows SELECT result = MAX(DATALENGTH(T.col05)) FROM dbo.Test AS T WHERE row_id BETWEEN 50 AND 100 ; But with a different query… -- Read all the data in column 1 SELECT result = MAX(DATALENGTH(T.col01)) FROM dbo.Test AS T ; …suddenly we have 49 LOB logical reads, as well as the ‘normal’ logical reads we would expect. The Explanation If we had tried to create this table in SQL Server 2000, we would have received a warning message to say that future INSERT or UPDATE operations on the table might fail if the resulting row exceeded the in-row storage limit of 8060 bytes.  If we needed to store more data than would fit in an 8060 byte row (including internal overhead) we had to use a LOB column – TEXT, NTEXT, or IMAGE.  These special data types store the large data values in a separate structure, with just a small pointer left in the original row. Row Overflow SQL Server 2005 introduced a feature called row overflow, which allows one or more variable-length columns in a row to move to off-row storage if the data in a particular row would otherwise exceed 8060 bytes.  You no longer receive a warning when creating (or altering) a table that might need more than 8060 bytes of in-row storage; if SQL Server finds that it can no longer fit a variable-length column in a particular row, it will silently move one or more of these columns off the row into a separate allocation unit. Only variable-length columns can be moved in this way (for example the (N)VARCHAR, VARBINARY, and SQL_VARIANT types).  Fixed-length columns (like INTEGER and DATETIME for example) never move into ‘row overflow’ storage.  The decision to move a column off-row is done on a row-by-row basis – so data in a particular column might be stored in-row for some table records, and off-row for others. In general, if SQL Server finds that it needs to move a column into row-overflow storage, it moves the largest variable-length column record for that row.  Note that in the case of an UPDATE statement that results in the 8060 byte limit being exceeded, it might not be the column that grew that is moved! Sneaky LOBs Anyway, that’s all very interesting but I don’t want to get too carried away with the intricacies of row-overflow storage internals.  The point is that it is now possible to define a table with non-LOB columns that will silently exceed the old row-size limit and result in ordinary variable-length columns being moved to off-row storage.  Adding new columns to a table, expanding an existing column definition, or simply storing more data in a column than you used to – all these things can result in one or more variable-length columns being moved off the row. Note that row-overflow storage is logically quite different from old-style LOB and new-style MAX data type storage – individual variable-length columns are still limited to 8000 bytes each – you can just have more of them now.  Having said that, the physical mechanisms involved are very similar to full LOB storage – a column moved to row-overflow leaves a 24-byte pointer record in the row, and the ‘separate storage’ I have been talking about is structured very similarly to both old-style LOBs and new-style MAX types.  The disadvantages are also the same: when SQL Server needs a row-overflow column value it needs to follow the in-row pointer a navigate another chain of pages, just like retrieving a traditional LOB. And Finally… In the example script presented above, the rows with row_id values from 402 to 450 inclusive all exceed the total in-row storage limit of 8060 bytes.  A SELECT that references a column in one of those rows that has moved to off-row storage will incur one or more lob logical reads as the storage engine locates the data.  The results on your system might vary slightly depending on your settings, of course; but in my tests only column 1 in rows 402-450 moved off-row.  You might like to play around with the script – updating columns, changing data type lengths, and so on – to see the effect on lob logical reads and which columns get moved when.  You might even see row-overflow columns moving back in-row if they are updated to be smaller (hint: reduce the size of a column entry by at least 1000 bytes if you hope to see this). Be aware that SQL Server will not warn you when it moves ‘ordinary’ variable-length columns into overflow storage, and it can have dramatic effects on performance.  It makes more sense than ever to choose column data types sensibly.  If you make every column a VARCHAR(8000) or NVARCHAR(4000), and someone stores data that results in a row needing more than 8060 bytes, SQL Server might turn some of your column data into pseudo-LOBs – all without saying a word. Finally, some people make a distinction between ordinary LOBs (those that can hold up to 2GB of data) and the LOB-like structures created by row-overflow (where columns are still limited to 8000 bytes) by referring to row-overflow LOBs as SLOBs.  I find that quite appealing, but the ‘S’ stands for ‘small’, which makes expanding the whole acronym a little daft-sounding…small large objects anyone? © Paul White 2011 email: [email protected] twitter: @SQL_Kiwi

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• Top 10 Browser Productivity Tips

  - by Renso

  Originally posted on: http://geekswithblogs.net/renso/archive/2013/10/14/top-10-browser-productivity-tips.aspxYou don’t have to be a geek to be a productive browser user. The tips below have been selected by actions users take most of the time to navigate a web-site but use long-standing keyboard or mouse actions to get them done, when there are keyboard short-cuts you can use instead. Since you hands are already on the keyboard it is almost always faster to sue a keyboard shortcut to get something done that you usually used the mouse for. For example right-clicking on something to copy it and then doing to same for pasting something is very time consuming, keyboard shortcuts have been created that simplify the task. All it takes are a few memory brain cells to remember them. Here are the tips, in no particular order:   Tip 1 Hold down the spacebar on your keyboard to page to the end of your web page rather than using your mouse. This is really a slow way of doing it. If you want to page one page at a time, hit the spacebar once, and again to page again. But if you want to page all the way to the end of the web page simply hit Ctrl+End (that is hold down the Ctrl key and hit the End button on your keyboard). To get to the top of your web page, simply hit Ctrl + Home to go all the way to the top of your web page. Tip 2 Where are my downloads? Some folks run downloads again-and-again because they do not know where the last one went and they do not see the popup, or browser note on their web page in the footer, etc. Simply hit Ctrl+J. Works in most browsers. Tip 3 Selecting a US state from a drop down box. Don’t use the mouse, takes just way too long to scroll. When you tab to the drop down box or click on it with your mouse, simply hit the first character of the state and it will be selected. For Texas for example hit the letter “T” twice on your keyboard to get to it. The same concept can be applied to any drop down box that is alphabetical or numerically sorted. Tip 4 Fixing spelling errors. All modern-day browsers support this now. You see the red wavy lines underscoring a word, yes it is a spelling error. How do you fix it? Don’t overtype it or try and fix it manually, fist right-click on it and a list of suggestions comes up. If it does not show up, like my name “Renso” and you know how to spell your name as in this example, look further down the list of options (the little window popup that appears when you right click) and you should see an option to “Add to Dictionary”. Be warned, when you add it, it only adds it to the browser you’re using’s dictionary. If you use Google Chrome, Firefox and IE, each one will have their own list. Tip 5 So you have trouble seeing the text on the screen. Or you are looking at a photo, for example in Facebook. You want to zoom in to read better or zoom into a photo a bit more. Hit Ctrl++ (hold down Ctrl key and hit the plus key – actually it’s the equal key but it is easier to remember that it is plus for bigger). Hit the minus to zoom out. Now you can’t remember what the original size was since you were so excited to hit it 20 times, or was that 21… Simply hit Ctrl+0 (that is zero) and it will reset it to the default. Tip 6 So you closed a couple of tabs in your browser. Suddenly you remember something you wanted to double-check something on one of the tabs, you cannot remember the URL ad the tab is gone forever, or is it? Simply hit Ctrl+Shift+t and it will bring back your tabs one by one each time you click the T. This has also been a great way for me to quickly close some tabs because I don’t want my boss to see I’m shopping and then hitting Ctrl+Shift+t to quickly get it back and complete my check-put and purchase. Or, for parents, when you walk into your daughter’s room and you see she quickly clicks and closes a window/tab in here browser. Not to worry my little darling, daddy will Ctrl+Shift+t and see what boys on Facebook you were talking too… Tip 7 The web browser is frozen on your PC/Laptop/Whatever, in this example it may be your Internet Explorer browser. I don’t mention Firefox or Chrome here because it probably never happens in their world. You cannot close it, it won’t respond to anything you have done s far except for the next step you are about to take, which is throw your two-day old coffee on your keyboard. This happens especially on sites that want to force you to complete a purchase order. Hit Ctrl+Alt+Del on your keyboard on any version of windows, select TASK MANAGER. In the  First Tab, which is the Process Tab, look for the item in question. In this example you should see Internet Explorer. Right-click it and select “End Task”. It will force the thread out of memory and terminate that process. You can of course do this with any program running under your account. Tip 8 This is a personal favorite of mine. To select words in the paragraph without using the mouse. You don’t want to select one character at a time like when you use the Ctrl+arrows as it can be very slow if you want to select a lot of text. You also want to select whole words. Simply use the Ctrl+Shift_arrow (right or left depending which direction you want to go. Tip 9 I was a bit reluctant to add this one, but being in the professional services industry still come across many-a-folk that simply can’t copy-and-paste them-all text or images that reside on them screens, y’all. Ctrl+c to copy and Ctrl+v to paste it. Works a lot faster than using the mouse. You may be asking: “Well why in the devil did they not use Ctrl+p for paste…. because that is for printing. This is of course not limited to the browser world, it applies to almost any piece of software running on PC or Mac. Go try it on an image on your browser, right-click it and select copy. Open a word document and Ctrl+v to paste the image in there. Please consider copyright laws. Tip 10 Getting rid of annoying ads. Now this only works when you load a web page, meaning when you get back to the same page later you will have to do this again and you will need to learn a tool to do it, WELL WORTH IT. For example, I use GrooveShark to listen to music but I don’t like the ads they show. Install a tool like Firebug for Firefox or use the Ctrl+Shift+I on Chrome to bring up the developer toolbar. Shows at the bottom of the page. With Firefox, once you have installed Firebug as an add-on, a yellow bug should appear on the top right-hand-side of your browser, click on it to display the developer toolbar. You will need to learn how to use it, but once you know how to select an item/section on the window (usually just right-click the add you don’t want to see and select “Inspect Element”, the developer toolbar will appear (if not already there)) and then simply hit delete and it will remove the add from the screen. If you don’t know HTML you may need to play with it a bit, but once you understand how it works can open up a whole new world for you on how web pages actually work. If you can think of any others that have saved you a ton of time please let me know so I can add them to a top 99 list.

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• Solaris 11 SRU / Update relationship explained, and blackout period on delivery of new bug fixes eliminated

  - by user12244672

  Relationship between SRUs and Update releases As you may know, Support Repository Updates (SRUs) for Oracle Solaris 11 are released monthly and are available to customers with an appropriate support contract.  SRUs primarily deliver bug fixes.  They may also deliver low risk feature enhancements. Solaris Update are typically released once or twice a year, containing support for new hardware, new software feature enhancements, and all bug fixes available at the time the Update content was finalized.  They also contain a significant number of new bug fixes, for issues found internally in Oracle and complex customer bug fixes which  require significant "soak" time to ensure their efficacy prior to release. Changes to SRU and Update Naming Conventions We're changing the naming convention of Update releases from a date based format such as Oracle Solaris 10 8/11 to a simpler "dot" version numbering, e.g. Oracle Solaris 11.1. Oracle Solaris 11 11/11 (i.e. the initial Oracle Solaris 11 release) may be referred to as 11.0. SRUs will simply be named as "dot.dot" releases, e.g. Oracle Solaris 11.1.1, for SRU1 after Oracle Solaris 11.1. Many Oracle products and infrastructure tools such as BugDB and MOS are tailored towards this "dot.dot" style of release naming, so these name changes align Oracle Solaris with these conventions. No Blackout Periods on Bug Fix Releases The Oracle Solaris 11 release process has been enhanced to eliminate blackout periods on the delivery of new bug fixes to customers. Previously, Oracle Solaris Updates were a superset of all preceding bug fix deliveries.  This made for a very simple update message - that which releases later is always a superset of that which was delivered previously. However, it had a downside.  Once the contents of an Update release were frozen prior to release, the release of new bug fixes for customer issues was also frozen to maintain the Update's superset relationship. Since the amount of change allowed into the final internal builds of an Update release is reduced to mitigate risk, this throttling back also impacted the release of new bug fixes to customers. This meant that there was effectively a 6 to 9 week hiatus on the release of new bug fixes prior to the release of each Update.  That wasn't good for customers awaiting critical bug fixes. We've eliminated this hiatus on the delivery of new bug fixes in Oracle Solaris 11 by allowing new bug fixes to continue to be released in SRUs even after the contents of the next Update release have been frozen. The release of SRUs will remain contiguous, with the first SRU released after the Update release effectively being a superset of both the the Update release and all preceding SRUs*.  That is, later SRUs are supersets of the content of previous SRUs. Therefore, the progression path from the final SRUs prior to the Update release is to the first SRU after the Update release, rather than to the Update release itself. The timeline / logical sequence of releases can be shown as follows: Updates: 11.0                                                11.1                               11.2     etc.                  \                                                         \                                    \ SRUs:       11.0.1, 11.0.2,...,11.0.12, 11.0.13, 11.1.1, 11.1.2,...,11.1.x, 11.2.1, etc. For example, for systems with Oracle Solaris 11 11/11 SRU12.4 or later installed, the recommended update path is to Oracle Solaris 11.1.1 (i.e. SRU1 after Solaris 11.1) or later rather than to the Solaris 11.1 release itself.  This will ensure no bug fixes are "lost" during the update. If for any reason you do wish to update from SRU12.4 or later to the 11.1 release itself - for example to update a test system - the instructions to do so are in the SRU12.4 README, https://updates.oracle.com/Orion/Services/download?type=readme&aru=15564533 For systems with Oracle Solaris 11 11/11 SRU11.4 or earlier installed, customers can update to either the 11.1 release or any 11.1 SRU as both will be supersets of their current version. Please do read the README of the SRU you are updating to, as it will contain important installation instructions which will save you time and effort. *Nerdy details: SRUs only contain the latest change delta relative to the Update on which they are based.  Their dependencies will, however, effectively pull in the Update content.  Customers maintaining a local Repo (e.g. behind their firewall), need to add both the 11.1 content and the relevant SRU content to their Repo, to enable the SRU's dependencies to be resolved.  Both will be available from the standard Support Repo and from MOS.  This is no different to existing SRUs for Oracle Solaris 11.0, whereby you may often get away with using just the SRU content to update, but the original 11.0 content may be needed in the Repo to resolve dependencies.

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• Possible SWITCH Optimization in DAX – #powerpivot #dax #tabular

  - by Marco Russo (SQLBI)

  In one of the Advanced DAX Workshop I taught this year, I had an interesting discussion about how to optimize a SWITCH statement (which could be frequently used checking a slicer, like in the Parameter Table pattern). Let’s start with the problem. What happen when you have such a statement? Sales :=     SWITCH (         VALUES ( Period[Period] ),         "Current", [Internet Total Sales],         "MTD", [MTD Sales],         "QTD", [QTD Sales],         "YTD", [YTD Sales],          BLANK ()     ) The SWITCH statement is in reality just syntax sugar for a nested IF statement. When you place such a measure in a pivot table, for every cell of the pivot table the IF options are evaluated. In order to optimize performance, the DAX engine usually does not compute cell-by-cell, but tries to compute the values in bulk-mode. However, if a measure contains an IF statement, every cell might have a different execution path, so the current implementation might evaluate all the possible IF branches in bulk-mode, so that for every cell the result from one of the branches will be already available in a pre-calculated dataset. The price for that could be high. If you consider the previous Sales measure, the YTD Sales measure could be evaluated for all the cells where it’s not required, and also when YTD is not selected at all in a Pivot Table. The actual optimization made by the DAX engine could be different in every build, and I expect newer builds of Tabular and Power Pivot to be better than older ones. However, we still don’t live in an ideal world, so it could be better trying to help the engine finding a better execution plan. One student (Niek de Wit) proposed this approach: Selection := IF (     HASONEVALUE ( Period[Period] ),     VALUES ( Period[Period] ) ) Sales := CALCULATE (     [Internet Total Sales],     FILTER (         VALUES ( 'Internet Sales'[Order Quantity] ),         'Internet Sales'[Order Quantity]             = IF (                 [Selection] = "Current",                 'Internet Sales'[Order Quantity],                 -1             )     ) )     + CALCULATE (         [MTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "MTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [QTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "QTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [YTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "YTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     ) At first sight, you might think it’s impossible that this approach could be faster. However, if you examine with the profiler what happens, there is a different story. Every original IF’s execution branch is now a separate CALCULATE statement, which applies a filter that does not execute the required measure calculation if the result of the FILTER is empty. I used the ‘Internet Sales’[Order Quantity] column in this example just because in Adventure Works it has only one value (every row has 1): in the real world, you should use a column that has a very low number of distinct values, or use a column that has always the same value for every row (so it will be compressed very well!). Because the value –1 is never used in this column, the IF comparison in the filter discharge all the values iterated in the filter if the selection does not match with the desired value. I hope to have time in the future to write a longer article about this optimization technique, but in the meantime I’ve seen this optimization has been useful in many other implementations. Please write your feedback if you find scenarios (in both Power Pivot and Tabular) where you obtain performance improvements using this technique!

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• Can Google Employees See My Saved Google Chrome Passwords?

  - by Jason Fitzpatrick

  Storing your passwords in your web browser seems like a great time saver, but are the passwords secure and inaccessible to others (even employees of the browser company) when squirreled away? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader MMA is curious if Google employees have (or could have) access to the passwords he stores in Google Chrome: I understand that we are really tempted to save our passwords in Google Chrome. The likely benefit is two fold, You don’t need to (memorize and) input those long and cryptic passwords. These are available wherever you are once you log in to your Google account. The last point sparked my doubt. Since the password is available anywhere, the storage must in some central location, and this should be at Google. Now, my simple question is, can a Google employee see my passwords? Searching over the Internet revealed several articles/messages. Do you save passwords in Chrome? Maybe you should reconsider: Talks about your passwords being stolen by someone who has access to your computer account. Nothing mentioned about the central storage security and vulnerability. There is even a response from Chrome browser security tech lead about the first issue. Chrome’s insane password security strategy: Mostly along the same line. You can steal password from somebody if you have access to the computer account. How to Steal Passwords Saved in Google Chrome in 5 Simple Steps: Teaches you how to actually perform the act mentioned in the previous two when you have access to somebody else’s account. There are many more (including this one at this site), mostly along the same line, points, counter-points, huge debates. I refrain from mentioning them here, simply carry a search if you want to find them. Coming back to my original query, can a Google employee see my password? Since I can view the password using a simple button, definitely they can be unhashed (decrypted) even if encrypted. This is very different from the passwords saved in Unix-like OS’s where the saved password can never be seen in plain text. They use a one-way encryption algorithm to encrypt your passwords. This encrypted password is then stored in the passwd or shadow file. When you attempt to login, the password you type in is encrypted again and compared with the entry in the file that stores your passwords. If they match, it must be the same password, and you are allowed access. Thus, a superuser can change my password, can block my account, but he can never see my password. So are his concerns well founded or will a little insight dispel his worry? The Answer SuperUser contributor Zeel helps put his mind at ease: Short answer: No* Passwords stored on your local machine can be decrypted by Chrome, as long as your OS user account is logged in. And then you can view those in plain text. At first this seems horrible, but how did you think auto-fill worked? When that password field gets filled in, Chrome must insert the real password into the HTML form element – or else the page wouldn’t work right, and you could not submit the form. And if the connection to the website is not over HTTPS, the plain text is then sent over the internet. In other words, if chrome can’t get the plain text passwords, then they are totally useless. A one way hash is no good, because we need to use them. Now the passwords are in fact encrypted, the only way to get them back to plain text is to have the decryption key. That key is your Google password, or a secondary key you can set up. When you sign into Chrome and sync the Google servers will transmit the encrypted passwords, settings, bookmarks, auto-fill, etc, to your local machine. Here Chrome will decrypt the information and be able to use it. On Google’s end all that info is stored in its encrpyted state, and they do not have the key to decrypt it. Your account password is checked against a hash to log in to Google, and even if you let chrome remember it, that encrypted version is hidden in the same bundle as the other passwords, impossible to access. So an employee could probably grab a dump of the encrypted data, but it wouldn’t do them any good, since they would have no way to use it.* So no, Google employees can not** access your passwords, since they are encrypted on their servers. * However, do not forget that any system that can be accessed by an authorized user can be accessed by an unauthorized user. Some systems are easier to break than other, but none are fail-proof. . . That being said, I think I will trust Google and the millions they spend on security systems, over any other password storage solution. And heck, I’m a wimpy nerd, it would be easier to beat the passwords out of me than break Google’s encryption. ** I am also assuming that there isn’t a person who just happens to work for Google gaining access to your local machine. In that case you are screwed, but employment at Google isn’t actually a factor any more. Moral: Hit Win + L before leaving machine. While we agree with zeel that it’s a pretty safe bet (as long as your computer is not compromised) that your passwords are in fact safe while stored in Chrome, we prefer to encrypt all our logins and passwords in a LastPass vault. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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• Fun with Aggregates

  - by Paul White

  There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT p.Name FROM Production.Product AS p JOIN Production.TransactionHistory AS th ON p.ProductID = th.ProductID GROUP BY p.ProductID, p.Name HAVING COUNT_BIG(*) < 10; That query correctly returns 23 rows (execution plan and data sample shown below): The execution plan looks a bit different from the written form of the query: the base tables are accessed in reverse order, and the aggregation is performed before the join.  The general idea is to read all rows from the history table, compute the count of rows grouped by ProductID, merge join the results to the Product table on ProductID, and finally filter to only return rows where the count is less than ten. This ‘fully-optimized’ plan has an estimated cost of around 0.33 units.  The reason for the quote marks there is that this plan is not quite as optimal as it could be – surely it would make sense to push the Filter down past the join too?  To answer that, let’s look at some other ways to formulate this query.  This being SQL, there are any number of ways to write logically-equivalent query specifications, so we’ll just look at a couple of interesting ones.  The first query is an attempt to reverse-engineer T-SQL from the optimized query plan shown above.  It joins the result of pre-aggregating the history table to the Product table before filtering: SELECT p.Name FROM ( SELECT th.ProductID, cnt = COUNT_BIG(*) FROM Production.TransactionHistory AS th GROUP BY th.ProductID ) AS q1 JOIN Production.Product AS p ON p.ProductID = q1.ProductID WHERE q1.cnt < 10; Perhaps a little surprisingly, we get a slightly different execution plan: The results are the same (23 rows) but this time the Filter is pushed below the join!  The optimizer chooses nested loops for the join, because the cardinality estimate for rows passing the Filter is a bit low (estimate 1 versus 23 actual), though you can force a merge join with a hint and the Filter still appears below the join.  In yet another variation, the < 10 predicate can be ‘manually pushed’ by specifying it in a HAVING clause in the “q1” sub-query instead of in the WHERE clause as written above. The reason this predicate can be pushed past the join in this query form, but not in the original formulation is simply an optimizer limitation – it does make efforts (primarily during the simplification phase) to encourage logically-equivalent query specifications to produce the same execution plan, but the implementation is not completely comprehensive. Moving on to a second example, the following query specification results from phrasing the requirement as “list the products where there exists fewer than ten correlated rows in the history table”: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) < 10 ); Unfortunately, this query produces an incorrect result (86 rows): The problem is that it lists products with no history rows, though the reasons are interesting.  The COUNT_BIG(*) in the EXISTS clause is a scalar aggregate (meaning there is no GROUP BY clause) and scalar aggregates always produce a value, even when the input is an empty set.  In the case of the COUNT aggregate, the result of aggregating the empty set is zero (the other standard aggregates produce a NULL).  To make the point really clear, let’s look at product 709, which happens to be one for which no history rows exist: -- Scalar aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709;   -- Vector aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709 GROUP BY th.ProductID; The estimated execution plans for these two statements are almost identical: You might expect the Stream Aggregate to have a Group By for the second statement, but this is not the case.  The query includes an equality comparison to a constant value (709), so all qualified rows are guaranteed to have the same value for ProductID and the Group By is optimized away. In fact there are some minor differences between the two plans (the first is auto-parameterized and qualifies for trivial plan, whereas the second is not auto-parameterized and requires cost-based optimization), but there is nothing to indicate that one is a scalar aggregate and the other is a vector aggregate.  This is something I would like to see exposed in show plan so I suggested it on Connect.  Anyway, the results of running the two queries show the difference at runtime: The scalar aggregate (no GROUP BY) returns a result of zero, whereas the vector aggregate (with a GROUP BY clause) returns nothing at all.  Returning to our EXISTS query, we could ‘fix’ it by changing the HAVING clause to reject rows where the scalar aggregate returns zero: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) BETWEEN 1 AND 9 ); The query now returns the correct 23 rows: Unfortunately, the execution plan is less efficient now – it has an estimated cost of 0.78 compared to 0.33 for the earlier plans.  Let’s try adding a redundant GROUP BY instead of changing the HAVING clause: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY th.ProductID HAVING COUNT_BIG(*) < 10 ); Not only do we now get correct results (23 rows), this is the execution plan: I like to compare that plan to quantum physics: if you don’t find it shocking, you haven’t understood it properly :)  The simple addition of a redundant GROUP BY has resulted in the EXISTS form of the query being transformed into exactly the same optimal plan we found earlier.  What’s more, in SQL Server 2008 and later, we can replace the odd-looking GROUP BY with an explicit GROUP BY on the empty set: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ); I offer that as an alternative because some people find it more intuitive (and it perhaps has more geek value too).  Whichever way you prefer, it’s rather satisfying to note that the result of the sub-query does not exist for a particular correlated value where a vector aggregate is used (the scalar COUNT aggregate always returns a value, even if zero, so it always ‘EXISTS’ regardless which ProductID is logically being evaluated). The following query forms also produce the optimal plan and correct results, so long as a vector aggregate is used (you can probably find more equivalent query forms): WHERE Clause SELECT p.Name FROM Production.Product AS p WHERE ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) < 10; APPLY SELECT p.Name FROM Production.Product AS p CROSS APPLY ( SELECT NULL FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ) AS ca (dummy); FROM Clause SELECT q1.Name FROM ( SELECT p.Name, cnt = ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) FROM Production.Product AS p ) AS q1 WHERE q1.cnt < 10; This last example uses SUM(1) instead of COUNT and does not require a vector aggregate…you should be able to work out why :) SELECT q.Name FROM ( SELECT p.Name, cnt = ( SELECT SUM(1) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID ) FROM Production.Product AS p ) AS q WHERE q.cnt < 10; The semantics of SQL aggregates are rather odd in places.  It definitely pays to get to know the rules, and to be careful to check whether your queries are using scalar or vector aggregates.  As we have seen, query plans do not show in which ‘mode’ an aggregate is running and getting it wrong can cause poor performance, wrong results, or both. © 2012 Paul White Twitter: @SQL_Kiwi email: [email protected]

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• CodePlex Daily Summary for Monday, May 26, 2014

  CodePlex Daily Summary for Monday, May 26, 2014Popular ReleasesClosedXML - The easy way to OpenXML: ClosedXML 0.71.1: More performance improvements. It's faster and consumes less memory.Role Based Views in Microsoft Dynamics CRM 2011: Role Based Views in CRM 2011 and 2013 - 1.1.0.0: Issues fixed in this build: 1. Works for CRM 2013 2. Lookup view not getting blockedSimCityPak: SimCityPak 0.3.1.0: Main New Features: Fixed Importing of Instance Names (get rid of the Dutch translations) Added advanced editor for Decal Dictionaries Added possibility to import .PNG to generate new decals Added advanced editor for Path display entriesSimple Connect To Db: SimpleConnectToDb_v1: SimpleConnectToDb_v1CRM 2011 / CRM 2013 Form Helper: v2014.05.25: v2014.05.25 Added PhoneFormat & PhoneFormatAreaCode v2014.05.24 Initial ReleaseCreate Word documents without MS Word: Release 3.0: Add support for Sections, Sections Headers and Footers and right to left languages.Corporate News App for SharePoint 2013: CorporateNewsApp v1.6.2.0: Important note This version contains a major bug fix about the generic error "Request failed. Unexpected response data from server null" This error occurs on SharePoint Online only, following an update of the Javascript API after May 2014. If you have installed this application manually in your applications company catalog, you can download the CorporateNewsApp.app file in the zip archive and update it manually. If you have installed this application directly from the SharePoint Store, it ...DevOS: DevOS: Plugin-system added Including:DevOS.exe DevOS API.dll Files must be in the some folderTiny Deduplicator: Tiny Deduplicator 1.0.1.0: Increased version number to 1.0.1.0 Moved all options to a separate 'Options' dialog window. Allows the user to specify a selection strategy which will help when dealing with large numbers of duplicate files. Available options are "None," "Keep First," and "Keep Last"C64 Studio: 3.5: Add: BASIC renumber function Add: !PET pseudo op Add: elseif for !if, } else { pseudo op Add: !TRACE pseudo op Add: Watches are saved/restored with a solution Add: Ctrl-A works now in export assembly controls Add: Preliminary graphic import dialog (not fully functional yet) Add: range and block selection in sprite/charset editor (Shift-Click = range, Alt-Click = block) Fix: Expression evaluator could miscalculate when both division and multiplication were in an expression without parenthesisSEToolbox: SEToolbox 01.031.009 Release 1: Added mirroring of ConveyorTubeCurved. Updated Ship cube rotation to rotate ship back to original location (cubes are reoriented but ship appears no different to outsider), and to rotate Grouped items. Repair now fixes the loss of Grouped controls due to changes in Space Engineers 01.030. Added export asteroids. Rejoin ships will merge grouping and conveyor systems (even though broken ships currently only maintain the Grouping on one part of the ship). Installation of this version wi...Player Framework by Microsoft: Player Framework for Windows and WP v2.0: Support for new Universal and Windows Phone 8.1 projects for both Xaml and JavaScript projects. See a detailed list of improvements, breaking changes and a general overview of version 2 ADDITIONAL DOWNLOADSSmooth Streaming Client SDK for Windows 8 Applications Smooth Streaming Client SDK for Windows 8.1 Applications Smooth Streaming Client SDK for Windows Phone 8.1 Applications Microsoft PlayReady Client SDK for Windows 8 Applications Microsoft PlayReady Client SDK for Windows 8.1 Applicat...TerraMap (Terraria World Map Viewer): TerraMap 1.0.6: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles Added the ability to select multiple highlighted block types. Added a dynamic, interactive highlight opacity slider, making it easier to find highlighted tiles with dark colors (and fixed blurriness from 1.0.5 alpha). Added ability to find Enchanted Swords (in the stone) and Water Bolt books Fixed Issue 35206: Hightlight/Find doesn't work for Demon Altars Fixed finding Demon Hearts/Shadow Orbs Fixed inst...DotNet.Highcharts: DotNet.Highcharts 4.0 with Examples: DotNet.Highcharts 4.0 Tested and adapted to the latest version of Highcharts 4.0.1 Added new chart type: Heatmap Added new type PointPlacement which represents enumeration or number for the padding of the X axis. Changed target framework from .NET Framework 4 to .NET Framework 4.5. Closed issues: 974: Add 'overflow' property to PlotOptionsColumnDataLabels class 997: Split container from JS 1006: Series/Categories with numeric names don't render DotNet.Highcharts.Samples Updated s...ConEmu - Windows console with tabs: ConEmu 140523 [Alpha]: ConEmu - developer build x86 and x64 versions. Written in C++, no additional packages required. Run "ConEmu.exe" or "ConEmu64.exe". Some useful information you may found: http://superuser.com/questions/tagged/conemu http://code.google.com/p/conemu-maximus5/wiki/ConEmuFAQ http://code.google.com/p/conemu-maximus5/wiki/TableOfContents If you want to use ConEmu in portable mode, just create empty "ConEmu.xml" file near to "ConEmu.exe" Aspose for Apache POI: Missing Features of Apache POI SL - v 1.1: Release contain the Missing Features in Apache POI SL SDK in Comparison with Aspose.Slides for dealing with Microsoft Power Point. What's New ?Following Examples: Managing Slide Transitions Manage Smart Art Adding Media Player Adding Audio Frame to Slide Feedback and Suggestions Many more examples are yet to come here. Keep visiting us. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.PowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.1.3: Added CompressLogs option to the config file. Each Install / Uninstall creates a timestamped zip file with all MSI and PSAppDeployToolkit logs contained within Added variable expansion to all paths in the configuration file Added documentation for each of the Toolkit internal variables that can be used Changed Install-MSUpdates to continue if any errors are encountered when installing updates Implement /Force parameter on Update-GroupPolicy (ensure that any logoff message is ignored) ...WordMat: WordMat v. 1.07: A quick fix because scientific notation was broken in v. 1.06 read more at http://wordmat.blogspot.com????: 《????》: 《????》（c???）??“????”???????，???????????????C?????????。???????,???????????????????????. ??????????????????????????????????；????????????????????????????。Mini SQL Query: Mini SQL Query (1.0.72.457): Apologies for the previous update! FK issue fixed and also a template data cache issue.New ProjectsASP.Net MCV4 Simplified Code Samples: This project intended to simplify the same. In this project each task is implemented with minimum lines of code to reduces complicity.Calvin: net???CodeLatino by Latinosoft: A Modified version for codeShow -- Probably taking more than a month.freeasyBackup: A free and easy to use Backup Tool for everyone. Without any cloud restrictions. freeasyExplorer: A free and easy to use File Explorer for everyone.openPDFspeedreader: #spritz #pdfreader #speedreader PDF Editor to Edit PDF Files in your ASP.NET Applications: This sample application allows the users to edit PDF files online using Aspose.Pdf for .NET.SharePoint World Cup 2013: world cup 2014SSAS Long Running Query Performance Helper: This utility helps investigate long running multidimensional or mining queries in discovery, de-parameterization and re-parameterization back to source format.

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• Exception Handling And Other Contentious Political Topics

  - by Justin Jones

  So about three years ago, around the time of my last blog post, I promised a friend I would write this post. Keeping promises is a good thing, and this is my first step towards easing back into regular blogging. I fully expect him to return from Pennsylvania to buy me a beer over this. However, it’s been an… ahem… eventful three years or so, and blogging, unfortunately, got pushed to the back burner on my priority list, along with a few other career minded activities. Now that the personal drama of the past three years is more or less resolved, it’s time to put a few things back on the front burner. What I consider to be proper exception handling practices is relatively well known these days. There are plenty of blog posts out there already on this topic which more or less echo my opinions on this topic. I’ll try to include a few links at the bottom of the post. Several years ago I had an argument with a co-worker who posited that exceptions should be caught at every level and logged. This might seem like sanity on the surface, but the resulting error log looked something like this: Error: System.SomeException Followed by small stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace.   These were all the same exception. The problem with this approach is that the error log, if you run any kind of analytics on in, becomes skewed depending on how far up the stack trace your exception was thrown. To mitigate this problem, we came up with the concept of the “PreLoggedException”. Basically, we would log the exception at the very top level and subsequently throw the exception back up the stack encapsulated in this pre-logged type, which our logging system knew to ignore. Now the error log looked like this: Error: System.SomeException Followed by small stack trace. Much cleaner, right? Well, there’s still a problem. When your exception happens in production and you go about trying to figure out what happened, you’ve lost more or less all context for where and how this exception was thrown, because all you really know is what method it was thrown in, but really nothing about who was calling the method or why. What gives you this clue is the entire stack trace, which we’re losing here. I believe that was further mitigated by having the logging system pull a system stack trace and add it to the log entry, but what you’re actually getting is the stack for how you got to the logging code. You’re still losing context about the actual error. Not to mention you’re executing a whole slew of catch blocks which are sloooooooowwwww……… In other words, we started with a bad idea and kept band-aiding it until it didn’t suck quite so bad. When I argued for not catching exceptions at every level but rather catching them following a certain set of rules, my co-worker warned me “do yourself a favor, never express that view in any future interviews.” I suppose this is my ultimate dismissal of that advice, but I’m not too worried. My approach for exception handling follows three basic rules: Only catch an exception if 1. You can do something about it. 2. You can add useful information to it. 3. You’re at an application boundary. Here’s what that means: 1. Only catch an exception if you can do something about it. We’ll start with a trivial example of a login system that uses a file. Please, never actually do this in production code, it’s just concocted example. So if our code goes to open a file and the file isn’t there, we get a FileNotFound exception. If the calling code doesn’t know what to do with this, it should bubble up. However, if we know how to create the file from scratch we can create the file and continue on our merry way. When you run into situations like this though, What should really run through your head is “How can I avoid handling an exception at all?” In this case, it’s a trivial matter to simply check for the existence of the file before trying to open it. If we detect that the file isn’t there, we can accomplish the same thing without having to handle in in a catch block. 2. Only catch an exception if you can do something about it. Continuing with the poorly thought out file based login system we contrived in part 1, if the code calls a Login(…) method and the FileNotFound exception is thrown higher up the stack, the code that calls Login must account for a FileNotFound exception. This is kind of counterintuitive because the calling code should not need to know the internals of the Login method, and the data file is an implementation detail. What makes more sense, assuming that we didn’t implement any of the good advice from step 1, is for Login to catch the FileNotFound exception and wrap it in a new exception. For argument’s sake we’ll say LoginSystemFailureException. (Sorry, couldn’t think of anything better at the moment.) This gives us two stack traces, preserving the original stack trace in the inner exception, and also is much more informative to the calling code. 3. Only catch an exception if you’re at an application boundary. At some point we have to catch all the exceptions, even the ones we don’t know what to do with. WinForms, ASP.Net, and most other UI technologies have some kind of built in mechanism for catching unhandled exceptions without fatally terminating the application. It’s still a good idea to somehow gracefully exit the application in this case if possible though, because you can no longer be sure what state your application is in, but nothing annoys a user more than an application just exploding. These unhandled exceptions need to be logged, and this is a good place to catch them. Ideally you never want this option to be exercised, but code as though it will be. When you log these exceptions, give them a “Fatal” status (e.g. Log4Net) and make sure these bugs get handled in your next release. That’s it in a nutshell. If you do it right each exception will only get logged once and with the largest stack trace possible which will make those 2am emergency severity 1 debugging sessions much shorter and less frustrating. Here’s a few people who also have interesting things to say on this topic:  http://blogs.msdn.com/b/ericlippert/archive/2008/09/10/vexing-exceptions.aspx http://www.codeproject.com/Articles/9538/Exception-Handling-Best-Practices-in-NET I know there’s more but I can’t find them at the moment.

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• GLSL: Strange light reflections [Solved]

  - by Tom

  According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image: Image1 in this image is a plane with two triangles and each of it is different illuminated (that is bad). The plane has 6 vertices. In the upper left side of this plane are 2 identical vertices (same in the lower right). Here are some vectors same for each vertice: normal vector = 0, 1, 0 (red lines on image) tangent vector = 0, 0,-1 (green lines on image) bitangent vector = -1, 0, 0 (blue lines on image) here I have one question: The two identical vertices does need to have the same tangent and bitangent? I have tried to make other values to the tangents but the effect was still similar. Here are my shaders Vertex shader: #version 130 // Input vertex data, different for all executions of this shader. in vec3 vertexPosition_modelspace; in vec2 vertexUV; in vec3 vertexNormal_modelspace; in vec3 vertexTangent_modelspace; in vec3 vertexBitangent_modelspace; // Output data ; will be interpolated for each fragment. out vec2 UV; out vec3 Position_worldspace; out vec3 EyeDirection_cameraspace; out vec3 LightDirection_cameraspace; out vec3 LightDirection_tangentspace; out vec3 EyeDirection_tangentspace; // Values that stay constant for the whole mesh. uniform mat4 MVP; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Output position of the vertex, in clip space : MVP * position gl_Position = MVP * vec4(vertexPosition_modelspace,1); // Position of the vertex, in worldspace : M * position Position_worldspace = (M * vec4(vertexPosition_modelspace,1)).xyz; // Vector that goes from the vertex to the camera, in camera space. // In camera space, the camera is at the origin (0,0,0). vec3 vertexPosition_cameraspace = ( V * M * vec4(vertexPosition_modelspace,1)).xyz; EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace; // Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity. vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz; LightDirection_cameraspace = LightPosition_cameraspace + EyeDirection_cameraspace; // UV of the vertex. No special space for this one. UV = vertexUV; // model to camera = ModelView vec3 vertexTangent_cameraspace = MV3x3 * vertexTangent_modelspace; vec3 vertexBitangent_cameraspace = MV3x3 * vertexBitangent_modelspace; vec3 vertexNormal_cameraspace = MV3x3 * vertexNormal_modelspace; mat3 TBN = transpose(mat3( vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace )); // You can use dot products instead of building this matrix and transposing it. See References for details. LightDirection_tangentspace = TBN * LightDirection_cameraspace; EyeDirection_tangentspace = TBN * EyeDirection_cameraspace; } Fragment shader: #version 130 // Interpolated values from the vertex shaders in vec2 UV; in vec3 Position_worldspace; in vec3 EyeDirection_cameraspace; in vec3 LightDirection_cameraspace; in vec3 LightDirection_tangentspace; in vec3 EyeDirection_tangentspace; // Ouput data out vec3 color; // Values that stay constant for the whole mesh. uniform sampler2D DiffuseTextureSampler; uniform sampler2D NormalTextureSampler; uniform sampler2D SpecularTextureSampler; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Light emission properties // You probably want to put them as uniforms vec3 LightColor = vec3(1,1,1); float LightPower = 40.0; // Material properties vec3 MaterialDiffuseColor = texture2D( DiffuseTextureSampler, vec2(UV.x,-UV.y) ).rgb; vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor; //vec3 MaterialSpecularColor = texture2D( SpecularTextureSampler, UV ).rgb * 0.3; vec3 MaterialSpecularColor = vec3(0.5,0.5,0.5); // Local normal, in tangent space. V tex coordinate is inverted because normal map is in TGA (not in DDS) for better quality vec3 TextureNormal_tangentspace = normalize(texture2D( NormalTextureSampler, vec2(UV.x,-UV.y) ).rgb*2.0 - 1.0); // Distance to the light float distance = length( LightPosition_worldspace - Position_worldspace ); // Normal of the computed fragment, in camera space vec3 n = TextureNormal_tangentspace; // Direction of the light (from the fragment to the light) vec3 l = normalize(LightDirection_tangentspace); // Cosine of the angle between the normal and the light direction, // clamped above 0 // - light is at the vertical of the triangle -> 1 // - light is perpendicular to the triangle -> 0 // - light is behind the triangle -> 0 float cosTheta = clamp( dot( n,l ), 0,1 ); // Eye vector (towards the camera) vec3 E = normalize(EyeDirection_tangentspace); // Direction in which the triangle reflects the light vec3 R = reflect(-l,n); // Cosine of the angle between the Eye vector and the Reflect vector, // clamped to 0 // - Looking into the reflection -> 1 // - Looking elsewhere -> < 1 float cosAlpha = clamp( dot( E,R ), 0,1 ); color = // Ambient : simulates indirect lighting MaterialAmbientColor + // Diffuse : "color" of the object MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) + // Specular : reflective highlight, like a mirror MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance); //color.xyz = E; //color.xyz = LightDirection_tangentspace; //color.xyz = EyeDirection_tangentspace; } I have replaced the original color value by EyeDirection_tangentspace vector and then I got other strange effect but I can not link the image (not eunogh reputation) Is it possible that with this shaders is something wrong, or maybe in other place in my code e.g with my matrices?

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• Master-slave vs. peer-to-peer archictecture: benefits and problems

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* 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-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• Best Practices - which domain types should be used to run applications

  - by jsavit

  This post is one of a series of "best practices" notes for Oracle VM Server for SPARC (formerly named Logical Domains) One question that frequently comes up is "which types of domain should I use to run applications?" There used to be a simple answer in most cases: "only run applications in guest domains", but enhancements to T-series servers, Oracle VM Server for SPARC and the advent of SPARC SuperCluster have made this question more interesting and worth qualifying differently. This article reviews the relevant concepts and provides suggestions on where to deploy applications in a logical domains environment. Review: division of labor and types of domain Oracle VM Server for SPARC offloads many functions from the hypervisor to domains (also called virtual machines). This is a modern alternative to using a "thick" hypervisor that provides all virtualization functions, as in traditional VM designs, This permits a simpler hypervisor design, which enhances reliability, and security. It also reduces single points of failure by assigning responsibilities to multiple system components, which further improves reliability and security. In this architecture, management and I/O functionality are provided within domains. Oracle VM Server for SPARC does this by defining the following types of domain, each with their own roles: Control domain - management control point for the server, used to configure domains and manage resources. It is the first domain to boot on a power-up, is an I/O domain, and is usually a service domain as well. I/O domain - has been assigned physical I/O devices: a PCIe root complex, a PCI device, or a SR-IOV (single-root I/O Virtualization) function. It has native performance and functionality for the devices it owns, unmediated by any virtualization layer. Service domain - provides virtual network and disk devices to guest domains. Guest domain - a domain whose devices are all virtual rather than physical: virtual network and disk devices provided by one or more service domains. In common practice, this is where applications are run. Typical deployment A service domain is generally also an I/O domain: otherwise it wouldn't have access to physical device "backends" to offer to its clients. Similarly, an I/O domain is also typically a service domain in order to leverage the available PCI busses. Control domains must be I/O domains, because they boot up first on the server and require physical I/O. It's typical for the control domain to also be a service domain too so it doesn't "waste" the I/O resources it uses. A simple configuration consists of a control domain, which is also the one I/O and service domain, and some number of guest domains using virtual I/O. In production, customers typically use multiple domains with I/O and service roles to eliminate single points of failure: guest domains have virtual disk and virtual devices provisioned from more than one service domain, so failure of a service domain or I/O path or device doesn't result in an application outage. This is also used for "rolling upgrades" in which service domains are upgraded one at a time while their guests continue to operate without disruption. (It should be noted that resiliency to I/O device failures can also be provided by the single control domain, using multi-path I/O) In this type of deployment, control, I/O, and service domains are used for virtualization infrastructure, while applications run in guest domains. Changing application deployment patterns The above model has been widely and successfully used, but more configuration options are available now. Servers got bigger than the original T2000 class machines with 2 I/O busses, so there is more I/O capacity that can be used for applications. Increased T-series server capacity made it attractive to run more vertical applications, such as databases, with higher resource requirements than the "light" applications originally seen. This made it attractive to run applications in I/O domains so they could get bare-metal native I/O performance. This is leveraged by the SPARC SuperCluster engineered system, announced a year ago at Oracle OpenWorld. In SPARC SuperCluster, I/O domains are used for high performance applications, with native I/O performance for disk and network and optimized access to the Infiniband fabric. Another technical enhancement is the introduction of Direct I/O (DIO) and Single Root I/O Virtualization (SR-IOV), which make it possible to give domains direct connections and native I/O performance for selected I/O devices. A domain with either a DIO or SR-IOV device is an I/O domain. In summary: not all I/O domains own PCI complexes, and there are increasingly more I/O domains that are not service domains. They use their I/O connectivity for performance for their own applications. However, there are some limitations and considerations: at this time, a domain using physical I/O cannot be live-migrated to another server. There is also a need to plan for security and introducing unneeded dependencies: if an I/O domain is also a service domain providing virtual I/O go guests, it has the ability to affect the correct operation of its client guest domains. This is even more relevant for the control domain. where the ldm has to be protected from unauthorized (or even mistaken) use that would affect other domains. As a general rule, running applications in the service domain or the control domain should be avoided. To recap: Guest domains with virtual I/O still provide the greatest operational flexibility, including features like live migration. I/O domains can be used for applications with high performance requirements. This is used to great effect in SPARC SuperCluster and in general T4 deployments. Direct I/O (DIO) and Single Root I/O Virtualization (SR-IOV) make this more attractive by giving direct I/O access to more domains. Service domains should in general not be used for applications, because compromised security in the domain, or an outage, can affect other domains that depend on it. This concern can be mitigated by providing guests' their virtual I/O from more than one service domain, so an interruption of service in the service domain does not cause an application outage. The control domain should in general not be used to run applications, for the same reason. SPARC SuperCluster use the control domain for applications, but it is an exception: it's not a general purpose environment; it's an engineered system with specifically configured applications and optimization for optimal performance. These are recommended "best practices" based on conversations with a number of Oracle architects. Keep in mind that "one size does not fit all", so you should evaluate these practices in the context of your own requirements. Summary Higher capacity T-series servers have made it more attractive to use them for applications with high resource requirements. New deployment models permit native I/O performance for demanding applications by running them in I/O domains with direct access to their devices. This is leveraged in SPARC SuperCluster, and can be leveraged in T-series servers to provision high-performance applications running in domains. Carefully planned, this can be used to provide higher performance for critical applications.

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• 5 Lessons learnt in localization / multi language support in WPF

  - by MarkPearl

  For the last few months I have been secretly working away at the second version of an application that we initially released a few years ago. It’s called MaxCut and it is a free panel/cut optimizer for the woodwork, glass and metal industry. One of the motivations for writing MaxCut was to get an end to end experience in developing an application for general consumption. From the early days of v1 of MaxCut I would get the odd email thanking me for the software and then listing a few suggestions on how to improve it. Two of the most dominant suggestions that we received were… Support for imperial measurements (the original program only supported the metric system) Multi language support (we had someone who volunteered to translate the program into Japanese for us). I am not going to dive into the Imperial to Metric support in todays blog post, but I would like to cover a few brief lessons we learned in adding support for multi-language functionality in the software. I have sectioned them below under different lessons. Lesson 1 – Build multi-language support in from the start So the first lesson I learnt was if you know you are going to do multi language support – build it in from the very beginning! One of the power points of WPF/Silverlight is data binding in XAML and so while it wasn’t to painful to retro fit multi language support into the programing, it was still time consuming and a bit tedious to go through mounds and mounds of views and would have been a minor job to have implemented this while the form was being designed. Lesson 2 – Accommodate for varying word lengths using Grids The next lesson was a little harder to learn and was learnt a bit further down the road in the development cycle. We developed everything in English, assuming that other languages would have similar character length words for equivalent meanings… don’t!. A word that is short in your language may be of varying character lengths in other languages. Some language like Dutch and German allow for concatenation of nouns which has the potential to create really long words. We picked up a few places where our views had been structured incorrectly so that if a word was to long it would get clipped off or cut out. To get around this we began using the WPF grid extensively with column widths that would automatically expand if they needed to. Generally speaking the grid replacement got round this hurdle, and if in future you have a choice between a stack panel or a grid – think twice before going for the easier option… often the grid will be a bit more work to setup, but will be more flexible. Lesson 3 – Separate the separators Our initial run through moving the words to a resource dictionary led us to make what I thought was one potential mistake. If we had a label like the following… “length : “ In the resource dictionary we put it as a single entry. This is fine until you start using a word more than once. For instance in our scenario we used the word “length’ frequently. with different variations of the word with grammar and separators included in the resource we ended up having what I would consider a bloated dictionary. When we removed the separators from the words and put them as their own resources we saw a dramatic reduction in dictionary size… so something that looked like this… “length : “ “length. “ “length?” Was reduced to… “length” “:” “?” “.” While this may not seem like a reduction at first glance, consider that the separators “:?.” are used everywhere and suddenly you see a real reduction in bloat. Lesson 4 – Centralize the Language Dictionary This lesson was learnt at the very end of the project after we had already had a release candidate out in the wild. Because our translations would be done on a volunteer basis and remotely, we wanted it to be really simple for someone to translate our program into another language. As a common design practice we had tiered the application so that we had a business logic layer, a ui layer, etc. The problem was in several of these layers we had resource files specific for that layer. What this resulted in was us having multiple resource files that we would need to send to our translators. To add to our problems, some of the wordings were duplicated in different resource files, which would result in additional frustration from our translators as they felt they were duplicating work. Eventually the workaround was to make a separate project in VS2010 with just the language translations. We then exposed the dictionary as public within this project and made it as a reference to the other projects within the solution. This solved out problem as now we had a central dictionary and could remove any duplication's. Lesson 5 – Make a dummy translation file to test that you haven’t missed anything The final lesson learnt about multi language support in WPF was when checking if you had forgotten to translate anything in the inline code, make a test resource file with dummy data. Ideally you want the data for each word to be identical. In our instance we made one which had all the resource key values pointing to a value of test. This allowed us point the language file to our test resource file and very quickly browse through the program and see if we had missed any linking. The alternative to this approach is to have two language files and swap between the two while running the program to make sure that you haven’t missed anything, but the downside of dual language file approach is that it is much a lot harder spotting a mistake if everything is different – almost like playing Where’s Wally / Waldo. It is much easier spotting variance in uniformity – meaning when you put the “test’ keyword for everything, anything that didn’t say “test” stuck out like a sore thumb. So these are my top five lessons learnt on implementing multi language support in WPF. Feel free to make any suggestions in the comments section if you feel maybe something is more important than one of these or if I got it wrong!

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• Alcatel-Lucent: Enterprise 2.0: The Top 5 Things I would Do Over

  - by Kellsey Ruppel

  Happy Monday! Does anyone else feel as if the weekend went entirely too quickly? At least for those of us in the United States, we have the 4th of July Holiday next week to look forward to This week on the blog, we are going to focus on "WebCenter by Example" and highlight best practices from customers and partners. I recently came across this article and I think this is a great example of how we can learn from one another when it comes to social collaboration adoption. Do you agree with Jem? What things or best practices have you learned in your organizations?  By Jem Janik, Enterprise community manager, Alcatel-Lucent  Not so long ago, Engage, the Alcatel-Lucent employee social network and collaboration platform, celebrated its third birthday. With more than 25,000 members actively interacting each month, Engage has been a big enough success that it’s been the subject of external articles, and often those of us who helped launch it will go out and speak about what aspects contributed to that success. Hindsight is still 20/20 and what it takes to successfully launch an enterprise 2.0 community is fairly well-known now.  Today I want to tell you what I suspect you really want to know about.  As the enterprise community manager for Engage, after three years in, what are the top 5 things I wish we (and I mostly mean me) could do over? #5 Define your analytics solution from the start There is so much to do when you launch a community and initially growing it without complete chaos is quite a task.  It doesn’t take too long to get to a point where you want to focus your continued efforts in growing company collaboration.  Do people truly talk across regional boundaries or have we shifted siloed conversations to a new platform.  Is there one organization that doesn’t interact with another? If you are lucky you’ll have someone in your community team well versed in the world of databases and SQL queries, but it takes time to figure out what backend analytics data actually means. Professional support can be expensive and it may be hard to justify later as it typically has the community manager as the only main customer.  Figure out what you think you’ll want to know and how to get it early on. The sooner the better even if it doesn’t seem that critical at the time. #4 Lobbies guide you to the right places One piece of feedback that comes up more and more as we keep growing Engage is it’s hard to find stuff, or new people are not sure where to start. Something we’re doing now is defining some general topic areas of interest to be like “lobbies” into the platform and some common hashtags to go with them. I liken this to walking into a large medical or professional building for the first time.  There are hundreds of offices, and you look to a sign in the lobby to get guided to the right place for you.  We’re building that sign for members now, but again we missed the boat as the majority of the company has had their initial Engage experience. #3 Clean up, clean up, clean up Knowledge work and folksonomies are messy! The day we opened the doors to Engage I would have said we should keep everything ever created in Engage with an argument that it was a window into our collective knowledge so nothing should go.  Well, 6000+ groups and 200,000+ pieces of content later, I’ve changed my mind.  As previously mentioned, with too much “stuff” the system can be overwhelming to new members and it makes it harder to get what you’re looking for.   Do we need that help document about a tool we no longer have? NO!  Do we need that group that had 1 document and 2 discussions in the last two years? NO! Should we only have one group about a given topic instead of 4?  YES! Last fall, Engage defined a cleanup process for groups not used for a long time.  We also formed a volunteer cleaning army who are extra eyes on the hunt for “stuff” that should be updated, merged, or deleted.  It’s better late than never, but in line with what’s becoming a theme I wish these efforts had started earlier. #2 Communications & local community management One of the most important aspects of my job is to make sure people who should be talking to each other are actually doing it.  Connecting people to the other people they should know, the groups they should join, a piece of content that shouldn’t be missed.   I have worked both inside and outside of communications teams, and they are the best informed people in your company.  They know when something big is coming, how it impacts employees, how it fits with strategy, who else knows more, etc.  Having communications professionals who are power users can help scale up community management because they are already so well connected.  They also need to have the platform skills to pay attention without suffering email overload, how to grab someone’s attention, etc.  I wish I’d had figured this out much earlier.  If I had I would have groomed more communications colleagues into advocates and power members right at the start. #1 Grooming advocates vs. natural advocates I’ve just alluded to this above already. The very best advocates are those who naturally embrace your platform and automatically start to see new ways to work within it.  Those advocates seem to come out of the woodwork naturally since some of them are early adopters.  Not surprisingly, our best advocates today are those same people who were willing to come kick the tires when the community was completely empty.  Unfortunately, we didn’t get a global spread of those natural advocates.  I did ask around when we first launched for other people who might be good candidates, but didn’t push too hard as there were so many other things to get ready.  That was a mistake.  If I could get a redo I would have formally asked for people to be assigned where there were gaps and groomed them into an advocate.  Today as we find new advocates to fill the gaps, people are hesitant as the initial set has three years of practice are ahead of the curve power members; it definitely would have been easier earlier on. As fairly early adopters to corporate scale enterprise collaboration, there hasn’t been a roadmap to follow as we’ve grown Engage, which is part of the fun! It’s clear a lot of issues are more easily tackled the earlier you identify and begin to correct them, and I’ve identified the main five I wish I could redo.  In the spirit of collaboration, I hope someone else learns from my mistakes! View the original article by Jem here. 

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• Effectiveness and Efficiency

  - by Daniel Moth

  In the professional environment, i.e. at work, I am always seeking personal growth and to be challenged. The result is that my assignments, my work list, my tasks, my goals, my commitments, my [insert whatever word resonates with you] keep growing (in scope and desired impact). Which in turn means I have to keep finding new ways to deliver more value, while not falling into the trap of working more hours. To do that I continuously evaluate both my effectiveness and my efficiency. EFFECTIVENESS The first thing I check is my effectiveness: Am I doing the right things? Am I focusing too much on unimportant things? Am I spending more time doing stuff that is important to my team/org/division/business/company, or am I spending it on stuff that is important to me and that I enjoy doing? Am I valuing activities that maybe I have outgrown and should be delegated to others who are at a stage I have surpassed (in Microsoft speak: is the work I am doing level appropriate or am I still operating at the previous level)? Notice how the answers to those questions change over time and due to certain events, so I have to remind myself to revisit them frequently. Events that force me to re-examine them are: change of role, change of team/org/etc, change of direction of team/org/etc, re-org, new hires on the team that take on some of the work I did, personal promotion, change of manager... and if none of those events has occurred since the last annual review, I ask myself those at each annual review anyway. If you think you are not being effective at work, make a list of the stuff that you do and start tracking where your time goes. In parallel, have a discussion with your manager about where they think your time should go. Ultimately your time is finite and hence it is your most precious investment, don't waste it. If your management doesn't value as highly what you spend your time on, then either convince your management, or stop spending your time on it, or find different management: Lead, Follow, or get out of the way! That's my view on effectiveness. You have to fix that before moving to being efficient, or you may end up being very efficient at stuff that nobody wants you to be doing in the first place. For example, you may be spending your time writing blog posts and becoming better and faster at it all the time. If your manager thinks that is not even part of your job description, you are wasting your time to satisfy your inner desires. Nobody can help you with your effectiveness other than your management chain and your management peers - they are the judges of it. EFFICIENCY The second thing I check is my efficiency: Am I doing things right? For me, doing things right means that I deliver the same quality of work faster [than what I used to, and than my peers, and than expected of me]. The result is that I can achieve more [than what I used to, and than my peers, and than expected of me]. Notice how the efficiency goal is a more portable one. If, by whatever criteria, you think you are the best at [insert your own skill here], this can change at two events: because you have new colleagues (who are potentially better than your older ones), and it can change with a change of manager (who has potentially higher expectations). That's about it. Once you are efficient at something, you carry that with you... All you need to really be doing here is, when taking on new kinds of work that you haven't done before, try a few approaches and devise a system so that you can become efficient at this new activity too... Just keep "collecting" stuff that you are efficient at. If you think you are not being efficient at something, break it down: What are the steps you take to complete that task? How long do you spend on each step? Talk to others about what steps they take, to see if you can optimize some steps away or trade them for better steps, or just learn how to complete a step faster. Have a system for every task you take so that you can have repeatable success. That's my view on efficiency. You have to fix it so that you can free up time to do more. When you plan a route from A to B - all else being equal - you try to get there as fast as possible so why would you not want to do that with your everyday work? For example, imagine you are inefficient at processing email: You spend more time than necessary dealing with email, and you still end up with dropped email threads and with slower response times than others. How can you improve? Talk to someone that you think is good at this, understand their system (e.g. here is my email processing system) and come up with one that works for you. Parting Thoughts Are you considered, by your colleagues and manager, an effective and efficient person at your workplace? If you are, what would you change if you were asked by your management to do the job of two people? Seriously, think about that! Your immediate reaction may be "that is not possible", but it actually is. You just have to re-assess what things that were previously important will now stop being important, by discussing them with your management and reaching agreement on relative priorities. For example, stuff that was previously on your plate may now have to be delegated or dropped. Where you thought you were efficient, maybe now you have to find an even faster path to completion, perhaps keeping in mind that Perfect is the Enemy of “Good Enough”. My personal experience (from both observing others and from my own reflection) is that when folks are struggling to keep up at work it is because of two reasons: They are investing energy in stuff that they enjoy doing which the business regards as having a lower priority than a lot of other things on their plate. They are completing tasks to a level of higher quality than what is required (due to personal pride) missing the big picture which almost always mandates completing three tasks at good enough quality than knocking only one of them out of the park while the other two come in late or not at all. There is a lot of content on the web, so I strongly encourage you to use your favorite search engine to read other views on effectiveness and efficiency (Bing, Google). Comments about this post by Daniel Moth welcome at the original blog.

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• Blogging locally and globally–my experience

  - by DigiMortal

  In Baltic MVP Summit 2011 there was discussion about having two blogs - one for local and another for global audience – and how to publish once written information in these blogs. There are many ways how to optimize your blogging activities if you have more than one audience and here you can find my experiences, best practices and advices about this topic. My two blogs I have to working blogs: this one here technology and programming blog for local market My local blog is almost five years old and it makes it one of the oldest company blogs in Estonia. It is still active and I write there as much as I have time for it. This blog here is active since September 2007, so it is about 3.5 years old right now. Both of these blogs are  my major hits in my MVP carrier and they have very good web statistics too. My local blog My local blog is about programming, web and technology. It has way wider target audience then this blog here has. By example, in my local blog I blog also about local events, cool new concept phones, different webs providing some interesting services etc. But local guys can find there also my postings about how to solve one or another programming problem and postings about Microsoft technologies I am playing with. This far my local blog has a lot of readers for such a small country that Estonia is. This blog has made me a lot of cool contacts and I have had there a lot of interesting discussions about different technical topics. Why I started this blog? Living in small country is different than living in big country. In small country you have less people and therefore smaller audience so you have to target more than one technical topic to find enough readers. In a same time you are still interested in your main topics and you want to reach to more people who are sharing same interests with you. Practically one day y will grow out from local market and you go global. This is how this blog was born. Was it worth to create, promote and mess with it? Every second I have put on my time to this blog has been worth of it. Thanks to this blog I have found new good friends and without them I think it is more boring to work on different problems and solutions. Defining target audiences One thing you should always do when having more than one blog is defining target audiences. If you are just technomaniac interested in sharing your stuff and make some new friends and have something to write to your MVP nomination form then you don’t have to go through complex targeting process. You can do it simple way and same effectively. Here is how I defined target audiences to my blogs: local blog – reader of my local blog is IT professional, software developer, technology innovator or just some guy who is interested in technology,   this blog – reader of this blog is experienced professional software developer who works on Microsoft technologies or software developer who is open minded and open to new technologies and interesting solutions to development problems. You can see how local blog – due to small market with less people – has wider definition for audience while this blog is heavily targeted to Microsoft technologies and specially to software development. On practical side these decisions are also made well I think because it is very hard to build up popular common IT blog. On global level it is better to target some specific niche and find readers who are professionals on your favorite topics. Thanks to this blog I have found new friends who are professional developers and I am very happy about all the discussions I have had with them. Publishing content to different blogs My local blog and this blog have some overlapping topics like .NET, databases and SEO. Due to this overlapping there is question: when I write posting to my local blog then should I have to publish same thing in my global blog? And if I write something to my global blog then should I publish same thing also in my local blog? Well, it really depends on the definition of your target audiences. If they match then of course it is good idea to translate you post and publish it also to another blog. But if you have different audiences then you may need to modify your posting before publishing it. The questions you have to answer are: is target audience interested in this topic? is target audience expecting more specific and deeper handling of this topic or are they expecting more general handling of topic? is the problem you are discussing actual for target audience or not? You have to answer these questions and after that make your decision. If you need to modify your original posting then take some time and do it. Provide quality to all your readers because they will respect you if you respect them. Cross-posting and referencing It is tempting to save time that preparing some blog post takes and if you have are done with posting in one blog it may seem like good idea to make short posting to another blog and add reference to first one where topic is discussed longer. Well, don’t do it – all your readers expect good quality content from you and jumping from one blog post to another is disturbing for them. Of course, there is problem with differences between target audiences. You may have wider target audience and some people may be interested in more specific handling of topic. In this case feel free to refer your blog you are writing in english. This is not working very well in opposite direction because almost all my global blog readers understand english but not estonian. By example, estonian language is complex one and online translating tools make very poor translations from estonian language. This is why I don’t even plan to publish postings here that refer to my local blog for more information. I am keeping these two blogs as two different worlds and if there is posting that fits well to both blogs I will write my posting to one blog and then answer previous three questions before posting same thing to another blog. Conclusion Growing out of your local market is not anything mysterious if you are living in small country. As it is harder to find people there who are interested in same topics with you then sooner or later you will start finding these new contacts from global audience. Global audience is bigger and to be visible there you must provide high quality content to your audience. It is something you will learn over time and you will learn every day something new when you are posting to your global blog. You may ask: if global blog is much more complex thing to do then is it worth to do at all? My answer is: yes, do it for sure. It is not easy thing to do when you start but if you work on your global blog and improve it over time you will get over all obstacles pretty soon. Just don’t forget one thing – content is king and your readers expect high quality from you.

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• Passing a parameter so that it cannot be changed – C#

  - by nmarun

  I read this requirement of not allowing a user to change the value of a property passed as a parameter to a method. In C++, as far as I could recall (it’s been over 10 yrs, so I had to refresh memory), you can pass ‘const’ to a function parameter and this ensures that the parameter cannot be changed inside the scope of the function. There’s no such direct way of doing this in C#, but that does not mean it cannot be done!! Ok, so this ‘not-so-direct’ technique depends on the type of the parameter – a simple property or a collection. Parameter as a simple property: This is quite easy (and you might have guessed it already). Bulent Ozkir clearly explains how this can be done here. Parameter as a collection property: Obviously the above does not work if the parameter is a collection of some type. Let’s dig-in. Suppose I need to create a collection of type KeyTitle as defined below. 1: public class KeyTitle 2: { 3: public int Key { get; set; } 4: public string Title { get; set; } 5: } My class is declared as below: 1: public class Class1 2: { 3: public Class1() 4: { 5: MyKeyTitleList = new List<KeyTitle>(); 6: } 7: 8: public List<KeyTitle> MyKeyTitleList { get; set; } 9: public ReadOnlyCollection<KeyTitle> ReadonlyKeyTitleCollection 10: { 11: // .AsReadOnly creates a ReadOnlyCollection<> type 12: get { return MyKeyTitleList.AsReadOnly(); } 13: } 14: } See the .AsReadOnly() method used in the second property? As MSDN says it: “Returns a read-only IList<T> wrapper for the current collection.” Knowing this, I can implement my code as: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8:  9: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 10:  11: Console.ReadLine(); 12: } 13:  14: private static void TryToModifyCollection(ReadOnlyCollection<KeyTitle> readOnlyCollection) 15: { 16: // can only read 17: for (int i = 0; i < readOnlyCollection.Count; i++) 18: { 19: Console.WriteLine("{0} - {1}", readOnlyCollection[i].Key, readOnlyCollection[i].Title); 20: } 21: // Add() - not allowed 22: // even the indexer does not have a setter 23: } The output is as expected: The below image shows two things. In the first line, I’ve tried to access an element in my read-only collection through an indexer. It shows that the ReadOnlyCollection<> does not have a setter on the indexer. The second line tells that there’s no ‘Add()’ method for this type of collection. The capture below shows there’s no ‘Remove()’ method either, there-by eliminating all ways of modifying a collection. Mission accomplished… right? Now, even if you have a collection of different type, all you need to do is to somehow cast (used loosely) it to a List<> and then do a .AsReadOnly() to get a ReadOnlyCollection of your custom collection type. As an example, if you have an IDictionary<int, string>, you can create a List<T> of this type with a wrapper class (KeyTitle in our case). 1: public IDictionary<int, string> MyDictionary { get; set; } 2:  3: public ReadOnlyCollection<KeyTitle> ReadonlyDictionary 4: { 5: get 6: { 7: return (from item in MyDictionary 8: select new KeyTitle 9: { 10: Key = item.Key, 11: Title = item.Value, 12: }).ToList().AsReadOnly(); 13: } 14: } Cool huh? Just one thing you need to know about the .AsReadOnly() method is that the only way to modify your ReadOnlyCollection<> is to modify the original collection. So doing: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 9:  10: Console.WriteLine(); 11:  12: class1.MyKeyTitleList.Add(new KeyTitle { Key = 5, Title = "mno" }); 13: class1.MyKeyTitleList[2] = new KeyTitle{Key = 3, Title = "GHI"}; 14: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 15:  16: Console.ReadLine(); 17: } Gives me the output of: See that the second element’s Title is changed to upper-case and the fifth element also gets displayed even though we’re still looping through the same ReadOnlyCollection<KeyTitle>. Verdict: Now you know of a way to implement ‘Method(const param1)’ in your code!

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• Testing Workflows &ndash; Test-First

  - by Timothy Klenke

  Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/05/30/testing-workflows-ndash-test-first.aspxThis is the second of two posts on some common strategies for approaching the job of writing tests.  The previous post covered test-after workflows where as this will focus on test-first.  Each workflow presented is a method of attack for adding tests to a project.  The more tools in your tool belt the better.  So here is a partial list of some test-first methodologies. Ping Pong Ping Pong is a methodology commonly used in pair programing.  One developer will write a new failing test.  Then they hand the keyboard to their partner.  The partner writes the production code to get the test passing.  The partner then writes the next test before passing the keyboard back to the original developer. The reasoning behind this testing methodology is to facilitate pair programming.  That is to say that this testing methodology shares all the benefits of pair programming, including ensuring multiple team members are familiar with the code base (i.e. low bus number). Test Blazer Test Blazing, in some respects, is also a pairing strategy.  The developers don’t work side by side on the same task at the same time.  Instead one developer is dedicated to writing tests at their own desk.  They write failing test after failing test, never touching the production code.  With these tests they are defining the specification for the system.  The developer most familiar with the specifications would be assigned this task. The next day or later in the same day another developer fetches the latest test suite.  Their job is to write the production code to get those tests passing.  Once all the tests pass they fetch from source control the latest version of the test project to get the newer tests. This methodology has some of the benefits of pair programming, namely lowering the bus number.  This can be good way adding an extra developer to a project without slowing it down too much.  The production coder isn’t slowed down writing tests.  The tests are in another project from the production code, so there shouldn’t be any merge conflicts despite two developers working on the same solution. This methodology is also a good test for the tests.  Can another developer figure out what system should do just by reading the tests?  This question will be answered as the production coder works there way through the test blazer’s tests. Test Driven Development (TDD) TDD is a highly disciplined practice that calls for a new test and an new production code to be written every few minutes.  There are strict rules for when you should be writing test or production code.  You start by writing a failing (red) test, then write the simplest production code possible to get the code working (green), then you clean up the code (refactor).  This is known as the red-green-refactor cycle. The goal of TDD isn’t the creation of a suite of tests, however that is an advantageous side effect.  The real goal of TDD is to follow a practice that yields a better design.  The practice is meant to push the design toward small, decoupled, modularized components.  This is generally considered a better design that large, highly coupled ball of mud. TDD accomplishes this through the refactoring cycle.  Refactoring is only possible to do safely when tests are in place.  In order to use TDD developers must be trained in how to look for and repair code smells in the system.  Through repairing these sections of smelly code (i.e. a refactoring) the design of the system emerges. For further information on TDD, I highly recommend the series “Is TDD Dead?”.  It discusses its pros and cons and when it is best used. Acceptance Test Driven Development (ATDD) Whereas TDD focuses on small unit tests that concentrate on a small piece of the system, Acceptance Tests focuses on the larger integrated environment.  Acceptance Tests usually correspond to user stories, which come directly from the customer. The unit tests focus on the inputs and outputs of smaller parts of the system, which are too low level to be of interest to the customer. ATDD generally uses the same tools as TDD.  However, ATDD uses fewer mocks and test doubles than TDD. ATDD often complements TDD; they aren’t competing methods.  A full test suite will usually consist of a large number of unit (created via TDD) tests and a smaller number of acceptance tests. Behaviour Driven Development (BDD) BDD is more about audience than workflow.  BDD pushes the testing realm out towards the client.  Developers, managers and the client all work together to define the tests. Typically different tooling is used for BDD than acceptance and unit testing.  This is done because the audience is not just developers.  Tools using the Gherkin family of languages allow for test scenarios to be described in an English format.  Other tools such as MSpec or FitNesse also strive for highly readable behaviour driven test suites. Because these tests are public facing (viewable by people outside the development team), the terminology usually changes.  You can’t get away with the same technobabble you can with unit tests written in a programming language that only developers understand.  For starters, they usually aren’t called tests.  Usually they’re called “examples”, “behaviours”, “scenarios”, or “specifications”. This may seem like a very subtle difference, but I’ve seen this small terminology change have a huge impact on the acceptance of the process.  Many people have a bias that testing is something that comes at the end of a project.  When you say we need to define the tests at the start of the project many people will immediately give that a lower priority on the project schedule.  But if you say we need to define the specification or behaviour of the system before we can start, you’ll get more cooperation.   Keep these test-first and test-after workflows in your tool belt.  With them you’ll be able to find new opportunities to apply them.

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