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• Free tools for analizing client-server comunication issues

  - by roberto

  Hi, we have some issues with a client-server based application and we would like to better understand client-server comunication without going to the software company that sold the application. At least we would like to perform the analysis in parallel. Can you suggest to me a dummy proof application that we can easily get and install to analise client-server traffic? Many thanks!

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• Using Excel, How do I Make a Column of Cells Equal One Other Cell?

  - by nicorellius

  I have a column of cells, all of which I want to equal the value in another cell. I highlight the cell and type = and then do that again below, and then I highlight the cells and drag down but the column of cells equals a parallel column of values. I want it to fix to one cell. Does this make sense? I'm sure it's easy but I cannot figure it out.

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• using Intellimouse in Parallels 5

  - by nobody

  I'm running Win7 in Parallels 5 and have a five button USB mouse (Microsoft Intellimouse). I have my mouse's side buttons mapped to the Forward and Back (browser) commands. However, Parallel's Mouse Synchronization Service seems to be intercepting the mouse keypress event for these two buttons, and remapping them to the Windows Start Menu command. Any way to undo this? i.e. get my Back/Forward buttons working again?

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• Parallelism in .NET – Part 16, Creating Tasks via a TaskFactory

  - by Reed

  The Task class in the Task Parallel Library supplies a large set of features.  However, when creating the task, and assigning it to a TaskScheduler, and starting the Task, there are quite a few steps involved.  This gets even more cumbersome when multiple tasks are involved.  Each task must be constructed, duplicating any options required, then started individually, potentially on a specific scheduler.  At first glance, this makes the new Task class seem like more work than ThreadPool.QueueUserWorkItem in .NET 3.5. In order to simplify this process, and make Tasks simple to use in simple cases, without sacrificing their power and flexibility, the Task Parallel Library added a new class: TaskFactory. The TaskFactory class is intended to “Provide support for creating and scheduling Task objects.”  Its entire purpose is to simplify development when working with Task instances.  The Task class provides access to the default TaskFactory via the Task.Factory static property.  By default, TaskFactory uses the default TaskScheduler to schedule tasks on a ThreadPool thread.  By using Task.Factory, we can automatically create and start a task in a single “fire and forget” manner, similar to how we did with ThreadPool.QueueUserWorkItem: Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides us with the same level of simplicity we had with ThreadPool.QueueUserWorkItem, but even more power.  For example, we can now easily wait on the task: // Start our task on a background thread var task = Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); // Do other work on the main thread, // while the task above executes in the background this.ExecuteWorkSynchronously(); // Wait for the background task to finish task.Wait(); TaskFactory simplifies creation and startup of simple background tasks dramatically. In addition to using the default TaskFactory, it’s often useful to construct a custom TaskFactory.  The TaskFactory class includes an entire set of constructors which allow you to specify the default configuration for every Task instance created by that factory.  This is particularly useful when using a custom TaskScheduler.  For example, look at the sample code for starting a task on the UI thread in Part 15: // Given the following, constructed on the UI thread // TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // When inside a background task, we can do string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); This is actually quite a bit more complicated than necessary.  When we create the uiScheduler instance, we can use that to construct a TaskFactory that will automatically schedule tasks on the UI thread.  To do that, we’d create the following on our main thread, prior to constructing our background tasks: // Construct a task scheduler from the current SynchronizationContext (UI thread) var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Construct a new TaskFactory using our UI scheduler var uiTaskFactory = new TaskFactory(uiScheduler); If we do this, when we’re on a background thread, we can use this new TaskFactory to marshal a Task back onto the UI thread.  Our previous code simplifies to: // When inside a background task, we can do string status = GetUpdatedStatus(); // Update our UI uiTaskFactory.StartNew( () => statusLabel.Text = status); Notice how much simpler this becomes!  By taking advantage of the convenience provided by a custom TaskFactory, we can now marshal to set data on the UI thread in a single, clear line of code!

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• How do you create a cbuffer or global variable that is gpu modifiable?

  - by bobobobo

  I'm implementing tonemapping in a pixel shader, for hdr lighting. The vertex shader outputs vertices with colors. I need to find the max color and save it in a global. However when I try and write the global in my hlsl code, //clamp the max color below by this color clamp( maxColor, output.color, float4( 1e6,1e6,1e6,1e6 ) ) ; I see: error X3025: global variables are implicitly constant, enable compatibility mode to allow modification What is the correct way to declare a shader global in d3d11 that the vertex shader can write to, and the pixel shader can read? I realize this is a bit tough since the vertex shaders are supposed to run in parallel, and introducing a shader global that they all write to means a lock..

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• Get started with C++ AMP

  - by Daniel Moth

  With the imminent release of Visual Studio 2012, even if you do not classify yourself as a C++ developer, C++ AMP is something you should learn so you can understand how to speed up your loops by offloading to the GPU the computation performed in the loop (assuming you have large number of iterations/data). We have many C# customers who are using C++ AMP through pinvoke, and of course many more directly from C++. So regardless of your programming language, I hope you'll find helpful these short videos that help you get started with C++ AMP C++ AMP core API introduction... from scratch Tiling Introduction - C++ AMP Matrix Multiplication with C++ AMP GPU debugging in Visual Studio 2012 In particular the work we have done for parallel and GPU debugging in Visual Studio 2012 is market leading, so check it out! Comments about this post by Daniel Moth welcome at the original blog.

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• Visual Studio 2010 released!

  Visual Studio 2010 releases to the word today. Get the full story from Soma's blog post (inc. links for buy, try etc). Our team is very proud of what we have contributed to this release and you can learn more about it through our content on the Parallel Computing MSDN home. Comments about this post welcome at the original blog. ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Introducing Microsoft SQL Server 2008 R2 - Business Intelligence Samples

  - by smisner

  On April 14, 2010, Microsoft Press (blog | twitter) released my latest book, co-authored with Ross Mistry (twitter), as a free ebook download - Introducing Microsoft SQL Server 2008 R2. As the title implies, this ebook is an introduction to the latest SQL Server release. Although you'll find a comprehensive review of the product's features in this book, you will not find the step-by-step details that are typical in my other books. For those readers who are interested in a more interactive learning experience, I have created two samples file for download: IntroSQLServer2008R2Samples project Sales Analysis workbook Here's a recap of the business intelligence chapters and the samples I used to generate the screen shots by chapter: Chapter 6: Scalable Data Warehousing covers a new edition of SQL Server, Parallel Data Warehouse. Understandably, Microsoft did not ship me the software and hardware to set up my own Parallel Data Warehouse environment for testing purposes and consequently you won't see any screenshots in this chapter. I received a lot of information and a lot of help from the product team during the development of this chapter to ensure its technical accuracy. Chapter 7: Master Data Services is a new component in SQL Server. After you install Master Data Services (MDS), which is a separate installation from SQL Server although it's found on the same media, you can install sample models to explore (which is what I did to create screenshots for the book). To do this, you deploying packages found at \Program Files\Microsoft SQL Server\Master Data Services\Samples\Packages. You will first need to use the Configuration Manager (in the Microsoft SQL Server 2008 R2\Master Data Services program group) to create a database and a Web application for MDS. Then when you launch the application, you'll see a Getting Started page which has a Deploy Sample Data link that you can use to deploy any of the sample packages. Chapter 8: Complex Event Processing is an introduction to another new component, StreamInsight. This topic was way too large to cover in-depth in a single chapter, so I focused on information such as architecture, development models, and an overview of the key sections of code you'll need to develop for your own applications. StreamInsight is an engine that operates on data in-flight and as such has no user interface that I could include in the book as screenshots. The November CTP version of SQL Server 2008 R2 included code samples as part of the installation, but these are not the official samples that will eventually be available in Codeplex. At the time of this writing, the samples are not yet published. Chapter 9: Reporting Services Enhancements provides an overview of all the changes to Reporting Services in SQL Server 2008 R2, and there are many! In previous posts, I shared more details than you'll find in the book about new functions (Lookup, MultiLookup, and LookupSet), properties for page numbering, and the new global variable RenderFormat. I will confess that I didn't use actual data in the book for my discussion on the Lookup functions, but I did create real reports for the blog posts and will upload those separately. For the other screenshots and examples in the book, I have created the IntroSQLServer2008R2Samples project for you to download. To preview these reports in Business Intelligence Development Studio, you must have the AdventureWorksDW2008R2 database installed, and you must download and install SQL Server 2008 R2. For the map report, you must execute the PopulationData.sql script that I included in the samples file to add a table to the AdventureWorksDW2008R2 database. The IntroSQLServer2008R2Samples project includes the following files: 01_AggregateOfAggregates.rdl to illustrate the use of embedded aggregate functions 02_RenderFormatAndPaging.rdl to illustrate the use of page break properties (Disabled, ResetPageNumber), the PageName property, and the RenderFormat global variable 03_DataSynchronization.rdl to illustrate the use of the DomainScope property 04_TextboxOrientation.rdl to illustrate the use of the WritingMode property 05_DataBar.rdl 06_Sparklines.rdl 07_Indicators.rdl 08_Map.rdl to illustrate a simple analytical map that uses color to show population counts by state PopulationData.sql to provide the data necessary for the map report Chapter 10: Self-Service Analysis with PowerPivot introduces two new components to the Microsoft BI stack, PowerPivot for Excel and PowerPivot for SharePoint, which you can learn more about at the PowerPivot site. To produce the screenshots for this chapter, I created the Sales Analysis workbook which you can download (although you must have Excel 2010 and the PowerPivot for Excel add-in installed to explore it fully). It's a rather simple workbook because space in the book did not permit a complete exploration of all the wonderful things you can do with PowerPivot. I used a tutorial that was available with the CTP version as a basis for the report so it might look familiar if you've already started learning about PowerPivot. In future posts, I'll continue exploring the new features in greater detail. If there's any special requests, please let me know! Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• OpenGL's matrix stack vs Hand multiplying

  - by deft_code

  Which is more efficient using OpenGL's transformation stack or applying the transformations by hand. I've often heard that you should minimize the number of state transitions in your graphics pipeline. Pushing and popping translation matrices seem like a big change. However, I wonder if the graphics card might be able to more than make up for pipeline hiccup by using its parallel execution hardware to bulk multiply the vertices. My specific case. I have font rendered to a sprite sheet. The coordinates of each character or a string are calculated and added to a vertex buffer. Now I need to move that string. Would it be better to iterate through the vertex buffer and adjust each of the vertices by hand or temporarily push a new translation matrix?

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• NET Math Libraries

  - by JoshReuben

  NET Mathematical Libraries   .NET Builder for Matlab The MathWorks Inc. - http://www.mathworks.com/products/netbuilder/ MATLAB Builder NE generates MATLAB based .NET and COM components royalty-free deployment creates the components by encrypting MATLAB functions and generating either a .NET or COM wrapper around them. .NET/Link for Mathematica www.wolfram.com a product that 2-way integrates Mathematica and Microsoft's .NET platform call .NET from Mathematica - use arbitrary .NET types directly from the Mathematica language. use and control the Mathematica kernel from a .NET program. turns Mathematica into a scripting shell to leverage the computational services of Mathematica. write custom front ends for Mathematica or use Mathematica as a computational engine for another program comes with full source code. Leverages MathLink - a Wolfram Research's protocol for sending data and commands back and forth between Mathematica and other programs. .NET/Link abstracts the low-level details of the MathLink C API. Extreme Optimization http://www.extremeoptimization.com/ a collection of general-purpose mathematical and statistical classes built for the.NET framework. It combines a math library, a vector and matrix library, and a statistics library in one package. download the trial of version 4.0 to try it out. Multi-core ready - Full support for Task Parallel Library features including cancellation. Broad base of algorithms covering a wide range of numerical techniques, including: linear algebra (BLAS and LAPACK routines), numerical analysis (integration and differentiation), equation solvers. Mathematics leverages parallelism using .NET 4.0's Task Parallel Library. Basic math: Complex numbers, 'special functions' like Gamma and Bessel functions, numerical differentiation. Solving equations: Solve equations in one variable, or solve systems of linear or nonlinear equations. Curve fitting: Linear and nonlinear curve fitting, cubic splines, polynomials, orthogonal polynomials. Optimization: find the minimum or maximum of a function in one or more variables, linear programming and mixed integer programming. Numerical integration: Compute integrals over finite or infinite intervals, over 2D and higher dimensional regions. Integrate systems of ordinary differential equations (ODE's). Fast Fourier Transforms: 1D and 2D FFT's using managed or fast native code (32 and 64 bit) BigInteger, BigRational, and BigFloat: Perform operations with arbitrary precision. Vector and Matrix Library Real and complex vectors and matrices. Single and double precision for elements. Structured matrix types: including triangular, symmetrical and band matrices. Sparse matrices. Matrix factorizations: LU decomposition, QR decomposition, singular value decomposition, Cholesky decomposition, eigenvalue decomposition. Portability and performance: Calculations can be done in 100% managed code, or in hand-optimized processor-specific native code (32 and 64 bit). Statistics Data manipulation: Sort and filter data, process missing values, remove outliers, etc. Supports .NET data binding. Statistical Models: Simple, multiple, nonlinear, logistic, Poisson regression. Generalized Linear Models. One and two-way ANOVA. Hypothesis Tests: 12 14 hypothesis tests, including the z-test, t-test, F-test, runs test, and more advanced tests, such as the Anderson-Darling test for normality, one and two-sample Kolmogorov-Smirnov test, and Levene's test for homogeneity of variances. Multivariate Statistics: K-means cluster analysis, hierarchical cluster analysis, principal component analysis (PCA), multivariate probability distributions. Statistical Distributions: 25 29 continuous and discrete statistical distributions, including uniform, Poisson, normal, lognormal, Weibull and Gumbel (extreme value) distributions. Random numbers: Random variates from any distribution, 4 high-quality random number generators, low discrepancy sequences, shufflers. New in version 4.0 (November, 2010) Support for .NET Framework Version 4.0 and Visual Studio 2010 TPL Parallellized – multicore ready sparse linear program solver - can solve problems with more than 1 million variables. Mixed integer linear programming using a branch and bound algorithm. special functions: hypergeometric, Riemann zeta, elliptic integrals, Frensel functions, Dawson's integral. Full set of window functions for FFT's. Product  Price Update subscription Single Developer License $999  $399  Team License (3 developers) $1999  $799  Department License (8 developers) $3999  $1599  Site License (Unlimited developers in one physical location) $7999  $3199    NMath http://www.centerspace.net .NET math and statistics libraries matrix and vector classes random number generators Fast Fourier Transforms (FFTs) numerical integration linear programming linear regression curve and surface fitting optimization hypothesis tests analysis of variance (ANOVA) probability distributions principal component analysis cluster analysis built on the Intel Math Kernel Library (MKL), which contains highly-optimized, extensively-threaded versions of BLAS (Basic Linear Algebra Subroutines) and LAPACK (Linear Algebra PACKage). Product  Price Update subscription Single Developer License $1295 $388 Team License (5 developers) $5180 $1554   DotNumerics http://www.dotnumerics.com/NumericalLibraries/Default.aspx free DotNumerics is a website dedicated to numerical computing for .NET that includes a C# Numerical Library for .NET containing algorithms for Linear Algebra, Differential Equations and Optimization problems. The Linear Algebra library includes CSLapack, CSBlas and CSEispack, ports from Fortran to C# of LAPACK, BLAS and EISPACK, respectively. Linear Algebra (CSLapack, CSBlas and CSEispack). Systems of linear equations, eigenvalue problems, least-squares solutions of linear systems and singular value problems. Differential Equations. Initial-value problem for nonstiff and stiff ordinary differential equations ODEs (explicit Runge-Kutta, implicit Runge-Kutta, Gear's BDF and Adams-Moulton). Optimization. Unconstrained and bounded constrained optimization of multivariate functions (L-BFGS-B, Truncated Newton and Simplex methods).   Math.NET Numerics http://numerics.mathdotnet.com/ free an open source numerical library - includes special functions, linear algebra, probability models, random numbers, interpolation, integral transforms. A merger of dnAnalytics with Math.NET Iridium in addition to a purely managed implementation will also support native hardware optimization. constants & special functions complex type support real and complex, dense and sparse linear algebra (with LU, QR, eigenvalues, ... decompositions) non-uniform probability distributions, multivariate distributions, sample generation alternative uniform random number generators descriptive statistics, including order statistics various interpolation methods, including barycentric approaches and splines numerical function integration (quadrature) routines integral transforms, like fourier transform (FFT) with arbitrary lengths support, and hartley spectral-space aware sequence manipulation (signal processing) combinatorics, polynomials, quaternions, basic number theory. parallelized where appropriate, to leverage multi-core and multi-processor systems fully managed or (if available) using native libraries (Intel MKL, ACMS, CUDA, FFTW) provides a native facade for F# developers

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• Microsoft Technical Computing

  In the past I have described the team I belong to here at Microsoft (Parallel Computing Platform) in terms of contributing to Visual Studio and related products, e.g. .NET Framework. To be more precise, our team is part of the Technical Computing group, which is still part of the Developer Division. This was officially announced externally earlier this month in an exec email (from Bob Muglia, the president of STB, to which DevDiv belongs). Here is an extract: " As we build the Technical...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Quick ways to boost performance and scalability of ASP.NET, WCF and Desktop Clients

  - by oazabir

  There are some simple configuration changes that you can make on machine.config and IIS to give your web applications significant performance boost. These are simple harmless changes but makes a lot of difference in terms of scalability. By tweaking system.net changes, you can increase the number of parallel calls that can be made from the services hosted on your servers as well as on desktop computers and thus increase scalability. By changing WCF throttling config you can increase number of simultaneous calls WCF can accept and thus make most use of your hardware power. By changing ASP.NET process model, you can increase number of concurrent requests that can be served by your website. And finally by turning on IIS caching and dynamic compression, you can dramatically increase the page download speed on browsers and and overall responsiveness of your applications. Read the CodeProject article for more details. http://www.codeproject.com/KB/webservices/quickwins.aspx Please vote for me if you find the article useful.

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• How to achieve best performance in DirectX 9.0 while rendering on multiple monitors

  - by Vibhore Tanwer

  I am new to DirectX, and trying to learn best practice. Please suggest what are the best practices for rendering on multiple monitors different things at the same time? how can I boost performance of application? I have gone through this article http://msdn.microsoft.com/en-us/library/windows/desktop/bb147263%28v=vs.85%29.aspx . I am making use of some pixel shaders to achieve some effects. At most 4 effect(4 shader effects) can be applied at same time. What are the best practices to achieve best performance with DirectX 9.0. I read somewhere that DirectX 11 provides support for parallel rendering, but I am not able to get any working sample for DirectX 11.0. Please help me with this, Any help would be of great value. Thanks

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• Data Warehouse Best Practices

  - by jean-pierre.dijcks

  In our quest to share our endless wisdom (ahem…) one of the things we figured might be handy is recording some of the best practices for data warehousing. And so we did. And, we did some more… We now have recreated our websites on Oracle Technology Network and have a separate page for best practices, parallelism and other cool topics related to data warehousing. But the main topic of this post is the set of recorded best practices. Here is what is available (and it is a series that ties together but can be read independently), applicable for almost any database version: Partitioning 3NF schema design for a data warehouse Star schema design Data Loading Parallel Execution Optimizer and Stats management The best practices page has a lot of other useful information so have a look here.

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• Billboard shader without distortion

  - by Nick Wiggill

  I use the standard approach to billboarding within Unity that is OK, but not ideal: transform.LookAt(camera). The problem is that this introduces distortion toward the edges of the viewport, especially as the field of view angle grows larger. This is unlike the perfect billboarding you'd see in eg. Doom when seeing an enemy from any angle and irrespective of where they are located in screen space. Obviously, there are ways to blit an image directly to the viewport, centred around a single vertex, but I'm not hot on shaders. Does anyone have any samples of this approach (GLSL if possible), or any suggestions as to why it isn't typically done this way (vs. the aforementioned quad transformation method)? EDIT: I was confused, thanks Nathan for the heads up. Of course, Causing the quads to look at the camera does not cause them to be parallel to the view plane -- which is what I need.

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• Does programming knowledge have a half-life?

  - by Gary Rowe

  In answering this question, I asserted that programming knowledge has a half-life of about 18 months. In physics, we have radioactive decay which is the process by which a radioactive element transforms into something less energetic. The half-life is the measure of how long it takes for this process to result in only half of the material to remain. A parallel concept might be that over time our programming knowledge ceases to be the current idiom and eventually becomes irrelevant. Noting that a half-life is asymptotic (so some knowledge will always be relevant), what are your thoughts on this? Is 18 months a good estimate? Is it even the case? Does it apply to design patterns, but over a longer period? What are the inherent advantages/disadvantages of this half-life? Update Just found this question which covers the material fairly well: "Half of everything you know will be obsolete in 18-24 months" = ( True, or False? )

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• Architectural requirements Q&amp;A

  A few days ago I was contacted by Lianping Chen a doctoral researcher from the Irish Software Engineering Research Centre. Lianping is doing research on how to elicit architectural significant requirements and he asked me a few questions, which I though, might be interesting to a wider audience. 1. Do you agree that architecture design and requirements elicitation are usually in parallel or have a big time overlap? In other words, Architectural...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• python, cluster computing, design help [closed]

  - by j dawg

  I would like to create my own parallel computing server. Can you please point me to some resources I can use to help me develop my server. Sorry, like I said I need help getting started. Yes, I am limited to python, I cannot use C. I am using a bunch of workstations and I want to use all the cpus in those machines. So what I am looking for is blog posts, books, articles that can help me develop my own client/server tools to send code from the client to the servers and spawn python processes based on the number of cpus. I know how to do the subprocessing/multiprocessing part of the program, I do not know how to create the server that will take the client's requests. I also need to figure out what is the best way to handle sending file data, like netcdf files or other spatial data. Any suggestions very welcome.

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• Technical Computing Initiative, Jim Gray and a Virtual Framed Letter on my Wall

  Today Microsoft announced their Technical Computing Initiative, a program to help scientists and engineers take advantage of the latest breakthroughs in parallel computing, bandwidth increases, and technologies that will make doing scientific research akin to using spreadsheets (as opposed to writing really complex custom code).  This is actually the culmination of work that the late Jim Gray, formerly a technical fellow at Microsoft, was working on. I didn't really know Jim, and frankly only...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Why lock-free data structures just aren't lock-free enough

  - by Alex.Davies

  Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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• Gilda Garretón, a Java Developer and Parallelism Computing Researcher

  - by Yolande

  In a new interview titled “Gilda Garretón, a Java Developer and Parallelism Computing Research,” Garretón shares her first-hand experience developing with Java and Java 7 for very large-scale integration (VLSI) of computer-aided design (CAD). Garretón gives an insightful overview of how Java is contributing to the parallelism development and to the Electric VLSI Design Systems, an open source VLSI CAD application used as a research platform for new CAD algorithms as well as the research flow for hardware test chips.  Garretón considers that parallelism programming is hard and complex, yet important developments are taking place.  "With the addition of the concurrent package in Java SE 6 and the Fork/Join feature in Java SE 7, developers have a chance to rely more on existing frameworks and dedicate more time to the essence of their parallel algorithms." Read the full article here  

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• Visual Studio Async CTP

  - by Daniel Moth

  While most of the buzz at the recent PDC here at Microsoft's headquarters has been about Windows Azure and Windows Phone, there is a truly noteworthy technology that as a .NET developer (of any kind of application) you should pay attention to, even in its early technology preview stage: Visual Studio Async CTP. I could provide many more direct links, but you do not need them: just visit the home page of this technology to download whitepapers, watch videos on how this technology integrates with C# and with VB, (through the new async and await language keywords) as well as videos on how the technology works under the covers (based largely on the Task Parallel Library). More importantly, download the actual bits (they install on top of your Visual Studio 2010), which include many samples. Get ready for a revolution in Asynchronous Programming with C# and Visual Basic. Comments about this post welcome at the original blog.

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• Well supported Hardware Raid Controller

  - by ftiaronsem

  Hello alltogether I am currently planning to buy a hardware-raid controller. This became necessary since I am running Linux and Windows in parallel and now need the redundancy for both OS (Im am going to use RAID1 / Mirroring). Therefore I am searching for a hardware raid controller which is well supported by linux / ubuntu (reporting smart values, stats for the harddrives, etc...). This controller should have four sata ports and if possible it should fit in a PCIE-1x Slot. I would greatly appreciate, if you could suggest some devices. Thanks in advance

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• SCCM2012 R2 – How to integrate MDT with SCCM

  - by Waclaw Chrabaszcz

  Originally posted on: http://geekswithblogs.net/Wchrabaszcz/archive/2013/11/12/sccm2012-r2--how-to-integrate-mdt-with-sccm.aspxThere are two maybe not competitive but parallel products: Microsoft Deployment Toolkit and System Center Configuration manager. Few years ago I was wondering why they are separate, I why I cannot share Task Sequences between them. And how it usually happens in live, when I was focused on other technologies, MDT and SCCM became best friends. Let's integrate MDT with SCCM: If first step you need to download MDT http://www.microsoft.com/en-us/download/details.aspx?id=25175 Install MDT on your SCCM server boxaccept the EULA Join CEIP if you like  Once you completed the installation I would recommend you to complete MDT configuring before integration with the SCCM. Start the Deployment Workbenchinstall updatesyou will need to download and install WAIKcreate new deployment shareleave default values Create MDT databaseMake sure you will create separate database, DO NOT use existing SCCM DB Now we are ready to integrate MDT with SCCMthe Integration tool should discover your server automaticallyAfter reopening SCCM console in task sequences you should have new cool features: How to use them? That's another story …

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• Oracle European Launch Event: Oracle Database In-Memory

  - by A&C Redaktion

  am 17. Juni wird Andy Mendelsohn,  Oracle Executive Vice President Database Server Technologies, als Keynote Speaker den europäischen Launch von  Oracle Database In-Memory  in Frankfurt im Radisson Blue Hotel eröffnen. Dieses Thema ist für unsere Partner und Kunden von zentraler Bedeutung. Daher ist auch die Agenda dieses Launch Events einzigartig:Neben Vorträgen von Betakunden (Postbank und Cern), dem Analysten von IDC, der auch beim HQ Launch eine Woche zuvor in Redwood Shores mit Larry Ellison auf der Bühne stehen wird, und weiteren Oracle-Experten finden auch Live Demos statt. Eine Podiumsdiskussion rundet das Programm ab. Parallel zum Event werden Presse- und Analystengespräche geführt.Mit der neuen, bahnbrechenden Oracle Database In-Memory Option profitieren Kunden von einer erheblich beschleunigten Datenbankleistung für Analytics, Data Warehousing, Reporting und Online Transaction Processing (OLTP).Das ist so revolutionär, dass wir hiermit alle unsere Partner und ihre Endkunden zu diesem herausragenden Event herzlich einladen .Hier können Sie sich und Ihre Endkunden zu dieser exklusiven Live-Veranstaltung anmelden

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