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  • How to Code Faster (Without Sacrificing Quality)

    - by ashes999
    I've been a professional coder for a several years. The comments about my code have generally been the same: writes great code, well-tested, but could be faster. So how do I become a faster coder, without sacrificing quality? For the sake of this question, I'm going to limit the scope to C#, since that's primarily what I code (for fun) -- or Java, which is similar enough in many ways that matter. Things that I'm already doing: Write the minimal solution that will get the job done Write a slew of automated tests (prevents regressions) Write (and use) reusable libraries for all kinds of things Use well-known technologies where they work well (eg. Hibernate) Use design patterns where they fit into place (eg. Singleton) These are all great, but I don't feel like my speed is increasing over time. I do care, because if I can do something to increase my productivity (even by 10%), that's 10% faster than my competitors. (Not that I have any.) Besides which, I've consistently gotten this feeback from my managers -- whether it was small-scale Flash development or enterprise Java/C++ development. Edit: There seem to be a lot of questions about what I mean by fast, and how I know I'm slow. Let me clarify with some more details. I worked in small and medium-sized teams (5-50 people) in various companies over various projects and various technologies (Flash, ASP.NET, Java, C++). The observation of my managers (which they told me directly) is that I'm "slow." Part of this is because a significant number of my peers sacrificed quality for speed; they wrote code that was buggy, hard to read, hard to maintain, and difficult to write automated tests for. My code generally is well-documented, readable, and testable. At Oracle, I would consistently solve bugs slower than other team-members. I know this, because I would get comments to that effect; this means that other (yes, more senior and experienced) developers could do my work in less time than it took me, at nearly the same quality (readability, maintainability, and testability). Why? What am I missing? How can I get better at this? My end goal is simple: if I can make product X in 40 hours today, and I can improve myself somehow so that I can create the same product at 20, 30, or even 38 hours tomorrow, that's what I want to know -- how do I get there? What process can I use to continually improve? I had thought it was about reusing code, but that's not enough, it seems.

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  • An MCM exam, Rob? Really?

    - by Rob Farley
    I took the SQL 2008 MCM Knowledge exam while in Seattle for the PASS Summit ten days ago. I wasn’t planning to do it, but I got persuaded to try. I was meaning to write this post to explain myself before the result came out, but it seems I didn’t get typing quickly enough. Those of you who know me will know I’m a big fan of certification, to a point. I’ve been involved with Microsoft Learning to help create exams. I’ve kept my certifications current since I first took an exam back in 1998, sitting many in beta, across quite a variety of topics. I’ve probably become quite good at them – I know I’ve definitely passed some that I really should’ve failed. I’ve also written that I don’t think exams are worth studying for. (That’s probably not entirely true, but it depends on your motivation. If you’re doing learning, I would encourage you to focus on what you need to know to do your job better. That will help you pass an exam – but the two skills are very different. I can coach someone on how to pass an exam, but that’s a different kind of teaching when compared to coaching someone about how to do a job. For example, the real world includes a lot of “it depends”, where you develop a feel for what the influencing factors might be. In an exam, its better to be able to know some of the “Don’t use this technology if XYZ is true” concepts better.) As for the Microsoft Certified Master certification… I’m not opposed to the idea of having the MCM (or in the future, MCSM) cert. But the barrier to entry feels quite high for me. When it was first introduced, the nearest testing centres to me were in Kuala Lumpur and Manila. Now there’s one in Perth, but that’s still a big effort. I know there are options in the US – such as one about an hour’s drive away from downtown Seattle, but it all just seems too hard. Plus, these exams are more expensive, and all up – I wasn’t sure I wanted to try them, particularly with the fact that I don’t like to study. I used to study for exams. It would drive my wife crazy. I’d have some exam scheduled for some time in the future (like the time I had two booked for two consecutive days at TechEd Australia 2005), and I’d make sure I was ready. Every waking moment would be spent pouring over exam material, and it wasn’t healthy. I got shaken out of that, though, when I ended up taking four exams in those two days in 2005 and passed them all. I also worked out that if I had a Second Shot available, then failing wasn’t a bad thing at all. Even without Second Shot, I’m much more okay about failing. But even just trying an MCM exam is a big effort. I wouldn’t want to fail one of them. Plus there’s the illusion to maintain. People have told me for a long time that I should just take the MCM exams – that I’d pass no problem. I’ve never been so sure. It was almost becoming a pride-point. Perhaps I should fail just to demonstrate that I can fail these things. Anyway – boB Taylor (@sqlboBT) persuaded me to try the SQL 2008 MCM Knowledge exam at the PASS Summit. They set up a testing centre in one of the room there, so it wasn’t out of my way at all. I had to squeeze it in between other commitments, and I certainly didn’t have time to even see what was on the syllabus, let alone study. In fact, I was so exhausted from the week that I fell asleep at least once (just for a moment though) during the actual exam. Perhaps the questions need more jokes, I’m not sure. I knew if I failed, then I might disappoint some people, but that I wouldn’t’ve spent a great deal of effort in trying to pass. On the other hand, if I did pass I’d then be under pressure to investigate the MCM Lab exam, which can be taken remotely (therefore, a much smaller amount of effort to make happen). In some ways, passing could end up just putting a bunch more pressure on me. Oh, and I did.

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  • SQL SERVER – Parsing SSIS Catalog Messages – Notes from the Field #030

    - by Pinal Dave
    [Note from Pinal]: This is a new episode of Notes from the Field series. SQL Server Integration Service (SSIS) is one of the most key essential part of the entire Business Intelligence (BI) story. It is a platform for data integration and workflow applications. The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data. In this episode of the Notes from the Field series I requested SSIS Expert Andy Leonard to discuss one of the most interesting concepts of SSIS Catalog Messages. There are plenty of interesting and useful information captured in the SSIS catalog and we will learn together how to explore the same. The SSIS Catalog captures a lot of cool information by default. Here’s a query I use to parse messages from the catalog.operation_messages table in the SSISDB database, where the logged messages are stored. This query is set up to parse a default message transmitted by the Lookup Transformation. It’s one of my favorite messages in the SSIS log because it gives me excellent information when I’m tuning SSIS data flows. The message reads similar to: Data Flow Task:Information: The Lookup processed 4485 rows in the cache. The processing time was 0.015 seconds. The cache used 1376895 bytes of memory. The query: USE SSISDB GO DECLARE @MessageSourceType INT = 60 DECLARE @StartOfIDString VARCHAR(100) = 'The Lookup processed ' DECLARE @ProcessingTimeString VARCHAR(100) = 'The processing time was ' DECLARE @CacheUsedString VARCHAR(100) = 'The cache used ' DECLARE @StartOfIDSearchString VARCHAR(100) = '%' + @StartOfIDString + '%' DECLARE @ProcessingTimeSearchString VARCHAR(100) = '%' + @ProcessingTimeString + '%' DECLARE @CacheUsedSearchString VARCHAR(100) = '%' + @CacheUsedString + '%' SELECT operation_id , SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1))) AS LookupRowsCount , SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1))) AS LookupProcessingTime , CASE WHEN (CONVERT(numeric(3,3),SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1))))) = 0 THEN 0 ELSE CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))) / CONVERT(numeric(3,3),SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1)))) END AS LookupRowsPerSecond , SUBSTRING(MESSAGE, (PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1)) - (PATINDEX(@CacheUsedSearchString, MESSAGE) + LEN(@CacheUsedString) + 1))) AS LookupBytesUsed ,CASE WHEN (CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))))= 0 THEN 0 ELSE CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1)) - (PATINDEX(@CacheUsedSearchString, MESSAGE) + LEN(@CacheUsedString) + 1)))) / CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))) END AS LookupBytesPerRow FROM [catalog].[operation_messages] WHERE message_source_type = @MessageSourceType AND MESSAGE LIKE @StartOfIDSearchString GO Note that you have to set some parameter values: @MessageSourceType [int] – represents the message source type value from the following results: Value     Description 10           Entry APIs, such as T-SQL and CLR Stored procedures 20           External process used to run package (ISServerExec.exe) 30           Package-level objects 40           Control Flow tasks 50           Control Flow containers 60           Data Flow task 70           Custom execution message Note: Taken from Reza Rad’s (excellent!) helper.MessageSourceType table found here. @StartOfIDString [VarChar(100)] – use this to uniquely identify the message field value you wish to parse. In this case, the string ‘The Lookup processed ‘ identifies all the Lookup Transformation messages I desire to parse. @ProcessingTimeString [VarChar(100)] – this parameter is message-specific. I use this parameter to specifically search the message field value for the beginning of the Lookup Processing Time value. For this execution, I use the string ‘The processing time was ‘. @CacheUsedString [VarChar(100)] – this parameter is also message-specific. I use this parameter to specifically search the message field value for the beginning of the Lookup Cache  Used value. It returns the memory used, in bytes. For this execution, I use the string ‘The cache used ‘. The other parameters are built from variations of the parameters listed above. The query parses the values into text. The string values are converted to numeric values for ratio calculations; LookupRowsPerSecond and LookupBytesPerRow. Since ratios involve division, CASE statements check for denominators that equal 0. Here are the results in an SSMS grid: This is not the only way to retrieve this information. And much of the code lends itself to conversion to functions. If there is interest, I will share the functions in an upcoming post. If you want to get started with SSIS with the help of experts, read more over at Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SSIS

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  • Emoti-phrases

    - by Tony Davis
    Surely the next radical step in the development of User-interface design is for applications to react appropriately to the rising tide of bewilderment, frustration or antipathy of the users. When an application understands that rapport is lost, it should respond accordingly. When we, for example, become confused by an unforgiving interface, shouldn't there be a way of signalling our bewilderment and having the application respond appropriately? There is surprisingly little in the current interface standards that would help. If we're getting frustrated with an unresponsive application, perhaps we could let it know of our increasing irritation by means of an "I'm getting angry and exasperated" slider. Although, by 'responding appropriately', I don't include playing a "we are experiencing unusually heavy traffic: your application usage is important to us" message, accompanied by calming muzak. When confronted with a tide of wizards, 'are you sure?' messages, or page-after-page of tiresome and barely-relevant options, how one yearns for a handy 'JFDI' (Just Flaming Do It) button. One click and the application miraculously desists with its annoying questions and just gets on with the job, using the defaults, or whatever we selected last time. Much more satisfying, and more direct to most developers and DBAs, however, would be the facility to communicate to the application via a twitter-style input field, or via parameters to command-line applications ("I don't want a wide-ranging debate with you; just open the bl**dy PDF!" or, or "Don't forget which of us has the close button"). Although to avoid too much cultural-dependence, perhaps we should take the lead from emoticons, and use a set of standardized emoti-phrases such as 'sez you', 'huh?', 'Pshaw!', or 'meh', which could be used to vent a range of feelings in any given application, whether it be SQL Server stubbornly refusing to give us the result we are expecting, or when an online-survey is getting too personal. Or a 'Lingua Glaswegia' perhaps: 'Atsabelter' ("very good") 'Atspish' ("must try harder") 'AnThenYerArsFellAff ' ("I don't quite trust these results") 'BileYerHeid' or 'ShutYerGub' ("please stop these inane questions") There would, of course, have to be an ANSI standards body to define the phrases that were acceptable. Presumably, there would be a tussle amongst the different international standards organizations. Meanwhile Oracle, Microsoft and Apple would each release non-standard extensions. Time then, surely, to plant emoti-phrases on the lot of them and develop a user-driven consensus. Send us your suggestions! The best one will win an iPod nano! Cheers! Tony.

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  • Data Mining Resources

    - by Dejan Sarka
    There are many different types of analyses, each one with its own pros and cons. Relational reports have a predefined structure, and end users cannot change it. They are simple to use for end users. Reports can use real-time data and snapshots of data to show the state of a report at specific points in time. One of the drawbacks is that report authoring is limited to IT pros and advanced users. Any kind of dynamic restructuring is very limited. If real-time data is used for a report, the report has a negative impact on the performance of the source system. Processing of the reports might be slow because the data comes from relational database management systems, which are not optimized for reporting only. If you create a semantic model of your data, your end users can create ad-hoc report structures. However, the development is more complex because a developer is needed to create these semantic models. For OLAP, you typically use specialized database management systems. You get lightning speed of analyses. End users can use rich and thin clients to interactively change the structure of the report. Typically, they do it graphically. However, the development of an OLAP system is many times quite complex. It involves the preparation and maintenance of an enterprise data warehouse and OLAP cubes. In order to exploit the possibility of real-time restructuring of reports, the users must be both active and educated. The data is usually stale, as it is loaded into data warehouses and OLAP cubes with a scheduled process. With data mining, a structure is not selected in advance; it searches for the structure. As a result, data mining can give you the most valuable results because you can discover patterns you did not expect. A data mining model structure is limited only by the attributes that you use to train the model. One of the drawbacks is that a lot of knowledge is needed for a successful data mining project. End users have to understand the results. Subject matter experts and IT professionals need to understand business problem thoroughly. The development might be sometimes even more complex than the development of OLAP cubes. Each type of analysis has its own place in an enterprise system. SQL Server has tools for all kinds of analyses. However, data mining is the most advanced way of analyzing the data; this is the “I” in BI. In order to get the most out of it, you need to learn quite a lot. In this blog post, I am gathering together resources for learning, including forthcoming events. Books Multiple authors: SQL Server MVP Deep Dives – I wrote an introductory data mining chapter there. Erik Veerman, Teo Lachev and Dejan Sarka: MCTS Self-Paced Training Kit (Exam 70-448): Microsoft SQL Server 2008 - Business Intelligence Development and Maintenance – you can find a good overview of a complete BI solution, including data mining, in this book. Jamie MacLennan, ZhaoHui Tang, and Bogdan Crivat: Data Mining with Microsoft SQL Server 2008 – can’t miss this book if you want to mine your data with SQL Server tools. Michael Berry, Gordon Linoff: Mastering Data Mining: The Art and Science of Customer Relationship Management – data mining from both, business and technical perspective. Dorian Pyle: Data Preparation for Data Mining – an in-depth book about data preparation. Thomas and Ronald Wonnacott: Introductory Statistics – if you thought that you could get away without statistics, then you are not serious about data mining. Jiawei Han and Micheline Kamber: Data Mining Concepts and Techniques – in-depth explanation of the most popular data mining algorithms. Michael Berry and Gordon Linoff: Data Mining Techniques – another book that explains data mining algorithms, more fro a business perspective. Paolo Guidici: Applied Data Mining – very mathematical book, only if you enjoy statistics and mathematics in general. Forthcoming presentations I am presenting two data mining related sessions during the PASS Summit in Charlotte, NC: Wednesday, October 16th, 2013 - Fraud Detection: Notes from the Field – I am showing how to use data mining for a specific business problem. The presentation is based on real-life projects. Friday, October 18th: Excel 2013 Advanced Analytics – I am focusing on Excel Data Mining Add-ins, and how to use them together with Power Pivot and other add-ins. This is the most you can get out of Excel. Sinergija 2013, Belgrade, Serbia Tuesday, October 22nd: Excel 2013 Analytics to the Max – another presentation focusing on the most advanced analytics you can get in Excel. SQL Rally Amsterdam, Netherlands Thursday, November 7th: Advanced Analytics in Excel 2013 – and again I am presenting about data mining in Excel. Why three different titles for the same presentation? I don’t know, I guess I forgot the name I proposed every time right after I sent the proposal. Courses Data Mining with SQL Server 2012 – I wrote a 3-day course for SolidQ. If you are interested in this course, which I could also deliver in a shorter seminar way, you can contact your closes SolidQ subsidiary, or, of course, me directly on addresses [email protected] or [email protected]. This course could also complement the existing courseware portfolio of training providers, which are welcome to contact me as well. OK, now you know: no more excuses, start learning data mining, get the most out of your data

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  • ORM Profiler v1.1 has been released!

    - by FransBouma
    We've released ORM Profiler v1.1, which has the following new features: Real time profiling A real time viewer (RTV) has been added, which gives insight in the activity as it is received by the client, in two views: a chronological connection overview and an activity graph overview. This RTV allows the user to directly record to a snapshot using record buttons, pause the view, mark a range to create a snapshot from that range, and view graphs about the # of connection open actions and # of commands per second. The RTV has a 'range' in which it keeps live data and auto-cleans data that's older than this range. Screenshot of the activity graphs part of the real-time viewer: Low-level activity tab A new tab has been added to the Application tabs: the Low-level activity tab. This tab shows the main activity as it has been received over the named pipe. It can help to get insight in the chronological activity without the grouping over connections, so multiple connections at the same time per thread are easier to spot. Clicking a command will sync the rest of the application tabs, clicking a row will show the details below the splitter bar, as it is done with the other application tabs as well. Default application name in interceptor When an empty string or null is passed for application name to the Initialize method of the interceptor, the AppDomain's friendly name is used instead. Copy call stack to clipboard A call stack viewed in a grid in various parts of the UI is now copyable to the clipboard by clicking a button. Enable/Disable interceptor from the config file It's now possible to enable/disable the interceptor Initialization from the application's config file, using: Code: <appSettings> <add key="ORMProfilerEnabled" value="true"/> </appSettings> if value is true, the interceptor's Initialize method will proceed. If the value is false, the interceptor's Initialize method will not proceed and initialization won't be performed, meaning no interception will take place. If the setting is absent, or misconfigured, the Initialize method will proceed as normal and perform the initialization. Stored procedure calls for select databases are now properly displayed as a call For the databases: SQL Server, Oracle, DB2, Sybase ASA, Sybase ASE and Informix a stored procedure call is displayed as an execute/call statement and copy to clipboard works as-is. I'm especially happy with the new real-time profiling feature in ORM Profiler, which is the flagship feature for this release: it offers a completely new way to use the profiler, namely directly during debugging: you can immediately see what's going on without the necessity of a snapshot. The activity graph feature combined with the auto-cleanup of older data, allows you to keep the profiler open for a long period of time and see any spike of activity on the profiled application.

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  • Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

    - by dotneteer
    Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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  • An MCM exam, Rob? Really?

    - by Rob Farley
    I took the SQL 2008 MCM Knowledge exam while in Seattle for the PASS Summit ten days ago. I wasn’t planning to do it, but I got persuaded to try. I was meaning to write this post to explain myself before the result came out, but it seems I didn’t get typing quickly enough. Those of you who know me will know I’m a big fan of certification, to a point. I’ve been involved with Microsoft Learning to help create exams. I’ve kept my certifications current since I first took an exam back in 1998, sitting many in beta, across quite a variety of topics. I’ve probably become quite good at them – I know I’ve definitely passed some that I really should’ve failed. I’ve also written that I don’t think exams are worth studying for. (That’s probably not entirely true, but it depends on your motivation. If you’re doing learning, I would encourage you to focus on what you need to know to do your job better. That will help you pass an exam – but the two skills are very different. I can coach someone on how to pass an exam, but that’s a different kind of teaching when compared to coaching someone about how to do a job. For example, the real world includes a lot of “it depends”, where you develop a feel for what the influencing factors might be. In an exam, its better to be able to know some of the “Don’t use this technology if XYZ is true” concepts better.) As for the Microsoft Certified Master certification… I’m not opposed to the idea of having the MCM (or in the future, MCSM) cert. But the barrier to entry feels quite high for me. When it was first introduced, the nearest testing centres to me were in Kuala Lumpur and Manila. Now there’s one in Perth, but that’s still a big effort. I know there are options in the US – such as one about an hour’s drive away from downtown Seattle, but it all just seems too hard. Plus, these exams are more expensive, and all up – I wasn’t sure I wanted to try them, particularly with the fact that I don’t like to study. I used to study for exams. It would drive my wife crazy. I’d have some exam scheduled for some time in the future (like the time I had two booked for two consecutive days at TechEd Australia 2005), and I’d make sure I was ready. Every waking moment would be spent pouring over exam material, and it wasn’t healthy. I got shaken out of that, though, when I ended up taking four exams in those two days in 2005 and passed them all. I also worked out that if I had a Second Shot available, then failing wasn’t a bad thing at all. Even without Second Shot, I’m much more okay about failing. But even just trying an MCM exam is a big effort. I wouldn’t want to fail one of them. Plus there’s the illusion to maintain. People have told me for a long time that I should just take the MCM exams – that I’d pass no problem. I’ve never been so sure. It was almost becoming a pride-point. Perhaps I should fail just to demonstrate that I can fail these things. Anyway – boB Taylor (@sqlboBT) persuaded me to try the SQL 2008 MCM Knowledge exam at the PASS Summit. They set up a testing centre in one of the room there, so it wasn’t out of my way at all. I had to squeeze it in between other commitments, and I certainly didn’t have time to even see what was on the syllabus, let alone study. In fact, I was so exhausted from the week that I fell asleep at least once (just for a moment though) during the actual exam. Perhaps the questions need more jokes, I’m not sure. I knew if I failed, then I might disappoint some people, but that I wouldn’t’ve spent a great deal of effort in trying to pass. On the other hand, if I did pass I’d then be under pressure to investigate the MCM Lab exam, which can be taken remotely (therefore, a much smaller amount of effort to make happen). In some ways, passing could end up just putting a bunch more pressure on me. Oh, and I did.

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  • Code Structure / Level Design: Plants vs Zombies game level dissection

    - by lalan
    Hi Friends, I am interested in learning the class structure of Plants vs Zombies, particularly level design; for those who haven't played it - this video contains nice play-through: http://www.youtube.com/watch?v=89DfdOIJ4xw. How would I go ahead and design the code, mostly structure & classes, which allows for maximum flexibility & clean development? I am familiar with data driven design concepts, and would use events to handle most of dynamic behavior. Dissection at macro level: (Once every Level) Load tilemap, props, etc -- basically build the map (Once every Level) Camera Movement - might consider it as short cut-scene (Once every Level) Show Enemies you'll face during present level (Once every Level) Unit Selection Window/Panel - selection of defensive plants (Once every Level) Camera Movement - might consider it as short cut-scene (Once every Level) HUD Creation - based on unit selection (Level Loop) Enemy creation - based on types of zombies allowed (Level Loop) Sun/Resource generation (Level Loop) Show messages like 'huge wave of zombies coming', 'final wave' (Level Loop) Other unique events - Spawn gifts, money, tombstones, etc (Once every Level) Unlock new plant Potential game scripts: a) Level definitions: Level_1_1.xml, Level_1_2.xml, etc. Level_1_1.xml :: Sample script <map> <tilemap>tilemapFrontLawn</tilemap> <SpawnPoints> tiles where particular type of zombies (land vs water) may spawn</spawnPoints> <props> position, entity array -- lawnmower, </props> </map> <zombies> <... list of zombies who gonna attack by ids...> </zombies> <plants> <... list by plants which are available for defense by ids...> </plants> <progression> <ZombieWave name='first wave' spawnScript='zombieLightWave.lua' unlock='null'> <startMessages time=1.5>Ready</startMessages> <endMessages time=1.5>Huge wave of zombies incoming</endMessages> </ZombieWave> </progression> b) Entities definitions: .xmls containing zombies, plants, sun, lawnmower, coins, etc description. Potential classes: //LevelManager - Based on the level under play, it will load level script. Few of the // functions it may have: class LevelManager { public: bool load(string levelFileName); bool enter(); bool update(float deltatime); bool exit(); private: LevelData* mLevelData; } // LevelData - Contains the details of level loaded by LevelManager. class LevelData { private: string file; // array of camera,dialog,attackwaves, etc in active level LevelCutSceneCamera** mArrayCutSceneCamera; LevelCutSceneDialog** mArrayCutSceneDialog; LevelAttackWave** mArrayAttackWave; .... // which camera,dialog,attackwave is active in level uint mCursorCutSceneCamera; uint mCursorCutSceneDialog; uint mCursorAttackWave; public: // based on cursor, get the next camera,dialog,attackwave,etc in active level // return false/true based on failure/success bool nextCutSceneCamera(LevelCutSceneCamera**); bool nextCutSceneDialog(LevelCutSceneDialog**); } // LevelUnderPlay- LevelManager class LevelUnderPlay { private: LevelCutSceneCamera* mCutSceneCamera; LevelCutSceneDialog* mCutSceneDialog; LevelAttackWave* mAttackWave; Entities** mSelectedPlants; Entities** mAllowedZombies; bool isCutSceneCameraActive; public: bool enter(); bool update(float deltatime); bool exit(); } I am totally confused.. :( Does it make sense of using class composition (have flat class hierarchy) for managing levels. Is it a good idea to just add/remove/update sprites (or any drawable stuff) to current scene from LevelManager or LevelUnderPlay? If I want to make non-linear level design, how should I go ahead? Perhaps I would need a LevelProgression class, which would decide what to do based on decision tree. Any suggestions would be appreciated very much. Thank for your time, lalan

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  • Create Orchard Module in a Separate Project

    - by Steve Michelotti
    The Orchard Project is a new OOS Microsoft project that is being developed up on CodePlex. From the Orchard home page on CodePlex, it states “Orchard project is focused on delivering a .NET-based CMS application that will allow users to rapidly create content-driven Websites, and an extensibility framework that will allow developers and customizers to provide additional functionality through modules and themes.” The Orchard Project site contains additional information including documentation and walkthroughs. The ability to create a composite solution based on a collection of modules is a compelling feature. In Orchard, these modules can just be created as simple MVC Areas or they can also be created inside of stand-alone web application projects.  The walkthrough for writing an Orchard module that is available on the Orchard site uses a simple Area that is created inside of the host application. It is based on the Orchard MIX presentation. This walkthrough does an effective job introducing various Orchard concepts such as hooking into the navigation system, theme/layout system, content types, and more.  However, creating an Orchard module in a separate project does not seem to be concisely documented anywhere. Orchard ships with several module OOTB that are in separate assemblies – but again, it’s not well documented how to get started building one from scratch. The following are the steps I took to successfully get an Orchard module in a separate project up and running. Step 1 – Download the OrchardIIS.zip file from the Orchard Release page. Unzip and open up the solution. Step 2 – Add your project to the solution. I named my project “Orchard.Widget” and used and “MVC 2 Empty Web Application” project type. Make sure you put the physical path inside the “Modules” sub-folder to the main project like this: At this point the solution should look like: Step 3 – Add assembly references to Orchard.dll and Orchard.Core.dll. Step 4 – Add a controller and view.  I’ll just create a Hello World controller and view. Notice I created the view as a partial view (*.ascx). Also add the [Themed] attribute to the top of the HomeController class just like the normal Orchard walk through shows it. Step 5 – Add Module.txt to the project root. The is a very important step. Orchard will not recognize your module without this text file present.  It can contain just the name of your module: name: Widget Step 6 – Add Routes.cs. Notice I’ve given an area name of “Orchard.Widget” on lines 26 and 33. 1: using System; 2: using System.Collections.Generic; 3: using System.Web.Mvc; 4: using System.Web.Routing; 5: using Orchard.Mvc.Routes; 6:   7: namespace Orchard.Widget 8: { 9: public class Routes : IRouteProvider 10: { 11: public void GetRoutes(ICollection<RouteDescriptor> routes) 12: { 13: foreach (var routeDescriptor in GetRoutes()) 14: { 15: routes.Add(routeDescriptor); 16: } 17: } 18:   19: public IEnumerable<RouteDescriptor> GetRoutes() 20: { 21: return new[] { 22: new RouteDescriptor { 23: Route = new Route( 24: "Widget/{controller}/{action}/{id}", 25: new RouteValueDictionary { 26: {"area", "Orchard.Widget"}, 27: {"controller", "Home"}, 28: {"action", "Index"}, 29: {"id", ""} 30: }, 31: new RouteValueDictionary(), 32: new RouteValueDictionary { 33: {"area", "Orchard.Widget"} 34: }, 35: new MvcRouteHandler()) 36: } 37: }; 38: } 39: } 40: } Step 7 – Add MainMenu.cs. This will make sure that an item appears in the main menu called “Widget” which points to the module. 1: using System; 2: using Orchard.UI.Navigation; 3:   4: namespace Orchard.Widget 5: { 6: public class MainMenu : INavigationProvider 7: { 8: public void GetNavigation(NavigationBuilder builder) 9: { 10: builder.Add(menu => menu.Add("Widget", item => item.Action("Index", "Home", new 11: { 12: area = "Orchard.Widget" 13: }))); 14: } 15:   16: public string MenuName 17: { 18: get { return "main"; } 19: } 20: } 21: } Step 8 – Clean up web.config. By default Visual Studio adds numerous sections to the web.config. The sections that can be removed are: appSettings, connectionStrings, authentication, membership, profile, and roleManager. Step 9 – Delete Global.asax. This project will ultimately be running from inside the Orchard host so this “sub-site” should not have its own Global.asax.   Now you’re ready the run the app.  When you first run it, the “Widget” menu item will appear in the main menu because of the MainMenu.cs file we added: We can then click the “Widget” link in the main menu to send us over to our view:   Packaging From start to finish, it’s a relatively painless experience but it could be better. For example, a Visual Studio project template that encapsulates aspects from this blog post would definitely make it a lot easier to get up and running with creating an Orchard module.  Another aspect I found interesting is that if you read the first paragraph of the walkthrough, it says, “You can also develop modules as separate projects, to be packaged and shared with other users of Orchard CMS (the packaging story is still to be defined, along with marketplaces for sharing modules).” In particular, I will be extremely curious to see how the “packaging story” evolves. The first thing that comes to mind for me is: what if we explored MvcContrib Portable Areas as a potential mechanism for this packaging? This would certainly make things easy since all artifacts (aspx, aspx, images, css, javascript) are all wrapped up into a single assembly. Granted, Orchard does have its own infrastructure for layouts and themes but it seems like integrating portable areas into this pipeline would not be a difficult undertaking. Maybe that’ll be the next research task. :)

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  • Trash Destination Adapter

    The Trash Destination and this article came from early experiences of using SSIS and community feedback at the time. When developing a package it is very useful to have a destination adapter that does nothing but consume rows with no setup requirement. You often want run a package part way through development, or just add a path so you can set a Data Viewer. There are stock tasks that can be used, but with the Trash Destination all columns are treated as selected automatically (usage type of read-only), so the pipeline knows they are required. It is also obvious that this is for development or diagnostic purposes, and is clearly not a part of the functional design of the package. It is also ideal for just playing around and exploring concepts in SSIS, and is often used in conjunction with the Data Generator Source. Using these two components it is easy to setup a test of an expression in the Derived Column Transformation for example. The Data Generator Source provides some dummy data, and the Trash Destination allows you to anchor the output path and set a Data Viewer to examine the results. It can also be used when performance tuning packages. It is a consistent and known quantity that has no external influences, so it is ideal as a destination when breaking the data flow into sections to isolate a bottleneck. The adapter is really simple to use and requires no setup. Simply drop it onto the pipeline designer and use it to terminate your data flow path. Installation The component is provided as an MSI file which you can download and run to install it. This simply places the files on disk in the correct locations and also installs the assemblies in the Global Assembly Cache as per Microsoft’s recommendations. You may need to restart the SQL Server Integration Services service, as this caches information about what components are installed, as well as restarting any open instances of Business Intelligence Development Studio (BIDS) / Visual Studio that you may be using to build your SSIS packages. Finally, for 2005/2008, you will have to add the transformation to the Visual Studio toolbox manually. Right-click the toolbox, and select Choose Items.... Select the SSIS Data Flow Items tab, and then check the Trash Destination transformation in the Choose Toolbox Items window. This process has been described in detail in the related FAQ entry for How do I install a task or transform component? We recommend you follow best practice and apply the current Microsoft SQL Server Service pack to your SQL Server servers and workstations. Downloads The Trash Destination is available for SQL Server 2005, SQL Server 2008 (includes R2) and SQL Server 2012. Please choose the version to match your SQL Server version, or you can install multiple versions and use them side by side if you have more than one version of SQL Server installed. Trash Destination for SQL Server 2005 Trash Destination for SQL Server 2008 Trash Destination for SQL Server 2012 Version History SQL Server 2012 Version 3.0.0.34 - SQL Server 2012 release. Includes upgrade support for both 2005 and 2008 packages to 2012. (5 Jun 2012) SQL Server 2008 Version 2.0.0.33 - SQL Server 2008 release. Includes support for upgrade of 2005 packages. RTM compatible, previously February 2008 CTP. (4 Mar 2008) Version 2.0.0.31 - SQL Server 2008 November 2007 CTP. (14 Feb 2008) SQL Server 2005 Version 1.0.2.18 - SQL Server 2005 RTM Refresh. SP1 Compatibility Testing. (12 Jun 2006) Version 1.0.1.1 - SQL Server 2005 IDW 15 June CTP. Minor enhancements over v1.0.1.0. (11 Jun 2005) Version 1.0.1.0 - SQL Server 2005 IDW 14 April CTP. First Public Release. (30 May 2005) Troubleshooting Make sure you have downloaded the version that matches your version of SQL Server. We offer separate downloads for SQL Server 2005, SQL Server 2008 and SQL Server 2012. If you an error when you try and use the component along the lines of The component could not be added to the Data Flow task. Please verify that this component is properly installed.  ... The data flow object "Konesans ..." is not installed correctly on this computer, this usually indicates that the internal cache of SSIS components needs to be updated. This is held by the SSIS service, so you need restart the the SQL Server Integration Services service. You can do this from the Services applet in Control Panel or Administrative Tools in Windows. You can also restart the computer if you prefer. You may also need to restart any current instances of Business Intelligence Development Studio (BIDS) / Visual Studio that you may be using to build your SSIS packages. The full error message is shown below for reference: TITLE: Microsoft Visual Studio ------------------------------ The component could not be added to the Data Flow task. Please verify that this component is properly installed. ------------------------------ ADDITIONAL INFORMATION: The data flow object "Konesans.Dts.Pipeline.TrashDestination.Trash, Konesans.Dts.Pipeline.TrashDestination, Version=1.0.1.0, Culture=neutral, PublicKeyToken=b8351fe7752642cc" is not installed correctly on this computer. (Microsoft.DataTransformationServices.Design) For 2005/2008, once installation is complete you need to manually add the task to the toolbox before you will see it and to be able add it to packages - How do I install a task or transform component? This is not necessary for SQL Server 2012 as the new SSIS toolbox automatically detects components. If you are still having issues then contact us, but please provide as much detail as possible about error, as well as which version of the the task you are using and details of the SSIS tools installed.

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  • Big Data – Various Learning Resources – How to Start with Big Data? – Day 20 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned how to become a Data Scientist for Big Data. In this article we will go over various learning resources related to Big Data. In this series we have covered many of the most essential details about Big Data. At the beginning of this series, I have encouraged readers to send me questions. One of the most popular questions is - “I want to learn more about Big Data. Where can I learn it?” This is indeed a great question as there are plenty of resources out to learn about Big Data and it is indeed difficult to select on one resource to learn Big Data. Hence I decided to write here a few of the very important resources which are related to Big Data. Learn from Pluralsight Pluralsight is a global leader in high-quality online training for hardcore developers.  It has fantastic Big Data Courses and I started to learn about Big Data with the help of Pluralsight. Here are few of the courses which are directly related to Big Data. Big Data: The Big Picture Big Data Analytics with Tableau NoSQL: The Big Picture Understanding NoSQL Data Analysis Fundamentals with Tableau I encourage all of you start with this video course as they are fantastic fundamentals to learn Big Data. Learn from Apache Resources at Apache are single point the most authentic learning resources. If you want to learn fundamentals and go deep about every aspect of the Big Data, I believe you must understand various concepts in Apache’s library. I am pretty impressed with the documentation and I am personally referencing it every single day when I work with Big Data. I strongly encourage all of you to bookmark following all the links for authentic big data learning. Haddop - The Apache Hadoop® project develops open-source software for reliable, scalable, distributed computing. Ambari: A web-based tool for provisioning, managing, and monitoring Apache Hadoop clusters which include support for Hadoop HDFS, Hadoop MapReduce, Hive, HCatalog, HBase, ZooKeeper, Oozie, Pig and Sqoop. Ambari also provides a dashboard for viewing cluster health such as heat maps and ability to view MapReduce, Pig and Hive applications visually along with features to diagnose their performance characteristics in a user-friendly manner. Avro: A data serialization system. Cassandra: A scalable multi-master database with no single points of failure. Chukwa: A data collection system for managing large distributed systems. HBase: A scalable, distributed database that supports structured data storage for large tables. Hive: A data warehouse infrastructure that provides data summarization and ad hoc querying. Mahout: A Scalable machine learning and data mining library. Pig: A high-level data-flow language and execution framework for parallel computation. ZooKeeper: A high-performance coordination service for distributed applications. Learn from Vendors One of the biggest issues with about learning Big Data is setting up the environment. Every Big Data vendor has different environment request and there are lots of things require to set up Big Data framework. Many of the users do not start with Big Data as they are afraid about the resources required to set up framework as well as a time commitment. Here Hortonworks have created fantastic learning environment. They have created Sandbox with everything one person needs to learn Big Data and also have provided excellent tutoring along with it. Sandbox comes with a dozen hands-on tutorial that will guide you through the basics of Hadoop as well it contains the Hortonworks Data Platform. I think Hortonworks did a fantastic job building this Sandbox and Tutorial. Though there are plenty of different Big Data Vendors I have decided to list only Hortonworks due to their unique setup. Please leave a comment if there are any other such platform to learn Big Data. I will include them over here as well. Learn from Books There are indeed few good books out there which one can refer to learn Big Data. Here are few good books which I have read. I will update the list as I will learn more. Ethics of Big Data Balancing Risk and Innovation Big Data for Dummies Head First Data Analysis: A Learner’s Guide to Big Numbers, Statistics, and Good Decisions If you search on Amazon there are millions of the books but I think above three books are a great set of books and it will give you great ideas about Big Data. Once you go through above books, you will have a clear idea about what is the next step you should follow in this series. You will be capable enough to make the right decision for yourself. Tomorrow In tomorrow’s blog post we will wrap up this series of Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • I can't start mysql in ubuntu 11.04

    - by shomid
    I downloaded following files of Oracle.com: MySQL-server-5.5.28-1.linux2.6.i386.rpm<br/> MySQL-client-5.5.28-1.linux2.6.i386.rpm<br/> MySQL-shared-5.5.28-1.linux2.6.i386.rpm<br/> then with "alien -i" command installing rpm packages and when starting mysql get following error: Starting MySQL<br/> .... * The server quit without updating PID file (/var/lib/mysql/omid-desktop.pid). error log: 121117 13:21:30 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 121117 13:21:30 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Table 'mysql.plugin' doesn't exist 121117 13:21:30 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 121117 13:21:30 InnoDB: The InnoDB memory heap is disabled 121117 13:21:30 InnoDB: Mutexes and rw_locks use InnoDB's own implementation 121117 13:21:30 InnoDB: Compressed tables use zlib 1.2.3 121117 13:21:30 InnoDB: Using Linux native AIO 121117 13:21:30 InnoDB: Initializing buffer pool, size = 128.0M 121117 13:21:30 InnoDB: Completed initialization of buffer pool 121117 13:21:30 InnoDB: highest supported file format is Barracuda. 121117 13:21:30 InnoDB: Waiting for the background threads to start 121117 13:21:31 InnoDB: 1.1.8 started; log sequence number 1595675 121117 13:21:31 [Note] Recovering after a crash using mysql-bin 121117 13:21:31 [Note] Starting crash recovery... 121117 13:21:31 [Note] Crash recovery finished. 121117 13:21:31 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306 121117 13:21:31 [Note] - '0.0.0.0' resolves to '0.0.0.0'; 121117 13:21:31 [Note] Server socket created on IP: '0.0.0.0'. 121117 13:21:31 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist 121117 13:21:31 mysqld_safe mysqld from pid file /var/lib/mysql/omid-desktop.pid ended 121117 13:25:38 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 121117 13:25:38 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Table 'mysql.plugin' doesn't exist 121117 13:25:38 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 121117 13:25:38 InnoDB: The InnoDB memory heap is disabled 121117 13:25:38 InnoDB: Mutexes and rw_locks use InnoDB's own implementation 121117 13:25:38 InnoDB: Compressed tables use zlib 1.2.3 121117 13:25:38 InnoDB: Using Linux native AIO 121117 13:25:38 InnoDB: Initializing buffer pool, size = 128.0M 121117 13:25:38 InnoDB: Completed initialization of buffer pool 121117 13:25:38 InnoDB: highest supported file format is Barracuda. 121117 13:25:38 InnoDB: Waiting for the background threads to start 121117 13:25:39 InnoDB: 1.1.8 started; log sequence number 1595675 /usr/sbin/mysqld: Too many arguments (first extra is 'start'). Use --verbose --help to get a list of available options 121117 13:25:39 [ERROR] Aborting 121117 13:25:39 InnoDB: Starting shutdown... 121117 13:25:40 InnoDB: Shutdown completed; log sequence number 1595675 121117 13:25:40 [Note] /usr/sbin/mysqld: Shutdown complete

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  • SQL SERVER – Difference Between CURRENT_TIMESTAMP and GETDATE() – CURRENT_TIMESTAMP Equivalent in SQL Server

    - by pinaldave
    A common question – I often get from Oracle/MySQL Professionals: “What is the Equivalent to CURRENT_TIMESTAMP in SQL Server?” Here is a common question I often get from SQL Server Professionals: “What are differences between Difference Between CURRENT_TIMESTAMP and GETDATE ()?” Very simple question but have showed up so frequently that I feel like to write about it. Well in SQL Server GETDATE() is Equivalent to CURRENT_TIMESTAMP. However, if you use CURRENT_TIMESTAMP in your select statement it will work fine. You can see in the above example – both of them returns the same value. Now let us go to next question regarding difference between GETDATE and CURRENT_TIMESTAMP. Well, the matter of the fact, there is no difference between them in SQL Server (Reference Link). CURRENT_TIMESTAMP is an ANSI SQL function, whereas GETDATE is T-SQL implementation of the same function. Both of them derive value from the operating system of the computer on which SQL Server instance is running. Above discussion prompts another question – in this case, what should one use GETDATE or CURRENT_TIMESTAMP? Well, this is indeed tricky and interesting question. I think I am very comfortable using the GETDATE () so I will go to use it but a matter of the fact there is no right or wrong answer. If you want to follow ancient saying “When in Rome, do as the Romans do”, I suggest using the GETDATE (), or continue using CURRENT_TIMESTAMP. With that said, there is one very important property we all need to keep in mind. If you use CURRENT_TIMESTAMP while creating an object, they are automatically converted to GETDATE() and stored internally. To illustrate what I am suggesting here is the example - Create a table using the following script CREATE TABLE [dbo].[TestTable]( [Cold2] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[TestTable] ADD DEFAULT (CURRENT_TIMESTAMP) FOR [Cold2] GO Now go to SSMS and generate the script for the table and you will notice following syntax. CREATE TABLE [dbo].[TestTable]( [Cold2] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[TestTable] ADD DEFAULT (GETDATE()) FOR [Cold2] GO You can notice that SQL Server have automatically converted CURRENT_TIMESTAMP to GETDATE(). I guess this gives us an idea how they behave. Now go ahead and make your choice! Do let me know which one will you use CURRENT_TIMESTAMP or GETDATE () in the comments area. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Online Password Security Tactics

    - by BuckWoody
    Recently two more large databases were attacked and compromised, one at the popular Gawker Media sites and the other at McDonald’s. Every time this kind of thing happens (which is FAR too often) it should remind the technical professional to ensure that they secure their systems correctly. If you write software that stores passwords, it should be heavily encrypted, and not human-readable in any storage. I advocate a different store for the login and password, so that if one is compromised, the other is not. I also advocate that you set a bit flag when a user changes their password, and send out a reminder to change passwords if that bit isn’t changed every three or six months.    But this post is about the *other* side – what to do to secure your own passwords, especially those you use online, either in a cloud service or at a provider. While you’re not in control of these breaches, there are some things you can do to help protect yourself. Most of these are obvious, but they contain a few little twists that make the process easier.   Use Complex Passwords This is easily stated, and probably one of the most un-heeded piece of advice. There are three main concepts here: ·         Don’t use a dictionary-based word ·         Use mixed case ·         Use punctuation, special characters and so on   So this: password Isn’t nearly as safe as this: P@ssw03d   Of course, this only helps if the site that stores your password encrypts it. Gawker does, so theoretically if you had the second password you’re in better shape, at least, than the first. Dictionary words are quickly broken, regardless of the encryption, so the more unusual characters you use, and the farther away from the dictionary words you get, the better.   Of course, this doesn’t help, not even a little, if the site stores the passwords in clear text, or the key to their encryption is broken. In that case…   Use a Different Password at Every Site What? I have hundreds of sites! Are you kidding me? Nope – I’m not. If you use the same password at every site, when a site gets attacked, the attacker will store your name and password value for attacks at other sites. So the only safe thing to do is to use different names or passwords (or both) at each site. Of course, most sites use your e-mail as a username, so you’re kind of hosed there. So even though you have hundreds of sites you visit, you need to have at least a different password at each site.   But it’s easier than you think – if you use an algorithm.   What I’m describing is to pick a “root” password, and then modify that based on the site or purpose. That way, if the site is compromised, you can still use that root password for the other sites.   Let’s take that second password: P@ssw03d   And now you can append, prepend or intersperse that password with other characters to make it unique to the site. That way you can easily remember the root password, but make it unique to the site. For instance, perhaps you read a lot of information on Gawker – how about these:   P@ssw03dRead ReadP@ssw03d PR@esasdw03d   If you have lots of sites, tracking even this can be difficult, so I recommend you use password software such as Password Safe or some other tool to have a secure database of your passwords at each site. DO NOT store this on the web. DO NOT use an Office document (Microsoft or otherwise) that is “encrypted” – the encryption office automation packages use is very trivial, and easily broken. A quick web search for tools to do that should show you how bad a choice this is.   Change Your Password on a Schedule I know. It’s a real pain. And it doesn’t seem worth it…until your account gets hacked. A quick note here – whenever a site gets hacked (and I find out about it) I change the password at that site immediately (or quit doing business with them) and then change the root password on every site, as quickly as I can.   If you follow the tip above, it’s not as hard. Just add another number, year, month, day, something like that into the mix. It’s not unlike making a Primary Key in an RDBMS.   P@ssw03dRead10242010   Change the site, and then update your password database. I do this about once a month, on the first or last day, during staff meetings. (J)   If you have other tips, post them here. We can all learn from each other on this.

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  • Becoming A Great Developer

    - by Lee Brandt
    Image via Wikipedia I’ve been doing the whole programming thing for awhile and reading and watching some of the best in the business. I have come to notice that the really great developers do a few things that (I think) makes them great. Now don’t get me wrong, I am not saying that I am one of these few. I still struggle with doing some of the things that makes one great at development. Coincidently, many of these things also make you a better person period. Believe That Guidance Is Better Than Answers This is one I have no problem with. I prefer guidance any time I am learning from another developer. Answers may get you going, but guidance will leave you stranded. At some point, you will come across a problem that can only be solved by thinking for yourself and this is where that guidance will really come in handy. You can use that guidance and extrapolate whatever technology to salve that problem (if it’s the right tool for solving that problem). The problem is, lots of developers simply want someone to tell them, “Do this, then this, then set that, and write this.” Favor thinking and learn the guidance of doing X and don’t ask someone to show you how to do X, if that makes sense. Read, Read and Read If you don’t like reading, you’re probably NOT going to make it into the Great Developer group. Great developers read books, they read magazines and they read code. Open source playgrounds like SourceForge, CodePlex and GitHub, have made it extremely easy to download code from developers you admire and see how they do stuff. Chances are, if you read their blog too, they’ll even explain WHY they did what they did (see “Guidance” above). MSDN and Code Magazine have not only code samples, but explanations of how to use certain technologies and sometimes even when NOT to use that same technology. Books are also out on just about every topic. I still favor the less technology centric books. For instance, I generally don’t buy books like, “Getting Started with Jiminy Jappets”. I look for titles like, “How To Write More Effective Code” (again, see guidance). The Addison-Wesley Signature Series is a great example of these types of books. They teach technology-agnostic concepts. Head First Design Patterns is another great guidance book. It teaches the "Gang Of Four" Design Patterns in a very easy-to-understand, picture-heavy way (I LIKE pictures). Hang Your Balls Out There Even though the advice came from a 3rd-shift Kinko’s attendant, doesn’t mean it’s not sound advice. Write some code and put it out for others to read, criticize and castigate you for. Understand that there are some real jerks out there who are absolute geniuses. Don’t be afraid to get some great advice wrapped in some really nasty language. Try to take what’s good about it and leave what’s not. I have a tough time with this myself. I don’t really have any code out there that is available for review (other than my demo code). It takes some guts to do, but in the end, there is no substitute for getting a community of developers to critique your code and give you ways to improve. Get Involved Speaking of community, the local and online user groups and discussion forums are a great place to hear about technologies and techniques you might never come across otherwise. Mostly because you might not know to look. But, once you sit down with a bunch of other developers and start discussing what you’re interested in, you may open up a whole new perspective on it. Don’t just go to the UG meetings and watch the presentations either, get out there and talk, socialize. I realize geeks weren’t meant to necessarily be social creatures, but if you’re amongst other geeks, it’s much easier. I’ve learned more in the last 3-4 years that I have been involved in the community that I did in my previous 8 years of coding without it. Socializing works, even if socialism doesn’t. Continuous Improvement Lean proponents might call this “Kaizen”, but I call it progress. We all know, especially in the technology realm, if you’re not moving ahead, you’re falling behind. It may seem like drinking from a fire hose, but step back and pick out the technologies that speak to you. The ones that may you’re little heart go pitter-patter. Concentrate on those. If you’re still overloaded, pick the best of the best. Just know that if you’re not looking at the code you wrote last week or at least last year with some embarrassment, you’re probably stagnating. That’s about all I can say about that, cause I am all out of clichés to throw at it. :0) Write Code Great painters paint, great writers write, and great developers write code. The most sure-fire way to improve your coding ability is to continue writing code. Don’t just write code that your work throws on you, pick that technology you love or are curious to know more about and walk through some blog demo examples. Take the language you use everyday and try to get it to do something crazy. Who knows, you might create the next Google search algorithm! All in all, being a great developer is about finding yourself in all this code. If it is just a job to you, you will probably never be one of the “Great Developers”, but you’re probably okay with that. If, on the other hand, you do aspire to greatness, get out there and GET it. No one’s going hand it to you.

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  • How to make creating viewmodels at runtime less painful

    - by Mr Happy
    I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painful. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genius since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use a DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an in-depth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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  • MSCC: Career & IT Fair 2014

    Already a couple of weeks ago, I've been addressed by Ibraahim and Yunus to see whether it would be interesting to participate in the 1st Career & IT Fair organised by the UoM Computer Club. Well, luckily we met at the Global Windows Azure Bootcamp and I wasn't too sure whether it would be possible for me to attend after all. The main reason is given because of work demand and furthermore due to the fact that the Mauritius Software Craftsmanship Community currently has no advertising material at all. Here's the brief statement of the event: "The UOM Students' Computer Club in collaboration with the UOM Students' Union and UOM CSE Department is organising a 'Career & IT Fair' on the 23rd and 24th April 2014. This event has for objective to provide a platform to tertiary students, secondary students as well as vocational students, the opportunity to meet job recruiters." Luckily, I was reminded that the 23rd is a Wednesday, and therefore I decided that it might be interesting to move our weekly Code & Coffee session to the university and hence be able to attend the career fair. As it turned out it was a great choice and thankfully Pritvi, Nadim as well as Ishwon volunteered to be around at the "community booth". Thankfully, the computer club gave us - the MSCC and the LUGM - one of their spaces in the lobby area of the Paul Octave Wiéhé Auditorium. My impression about the event Very well and professionally organised. Seriously, the lads over at the UoM Computer Club did a great job in organising their 2 days event, and felt very comfortable at any time. Actually, it was kind of amusing to some of the members constantly running around and checking everything. Even though that the whole process went smooth and easy off the hand. There were a couple of interesting pieces of information and announcements during the opening ceremony. For example, the Computer Science faculty is a very young one and has been initiated back in 1988 only - just by 4 staff members at that time. Now, after 25 years they have achieved quite a lot and there are currently 1.000+ active students attending the numerous lectures and courses. But there is no room to rest on previous achievements, and I was kind of surprised to hear that there are plans to extend the campus, and offer new lectures in the fields of nanotechnology, big data handling, and - crossing fingers - the introduction and establishment of a space control centre. Mauritius is already part of the Square Kilometre Array (SKA) and hopefully there will be more activities into that direction in the near future. Community - Awareness and collaboration As stated earlier, I could only spent one morning but luckily other members of the MSCC and the LUGM stayed during the whole two days and provided answers to any interested person. As for me, I took the opportunity to get in touch with the other companies in the lobby. Mainly, to create some awareness about our IT communities but also to see whether there might be options for future engagement in common activities, too. So far, I was able to speak to representatives of the following companies: ACCA Mauritius Business at Work Infomil LinkByNet Microsoft Indian Ocean Islands & French Pacific Spherinity Training Institute Spoon Consulting Ltd. State Informatics Ltd. Unfortunately, I only had a quick chat with an HR representative of LinkByNet but I fully count on our MSCC members like Nitin or LUGM member Ronny to spread our intentions over there.  So far, all of the representatives were really interested in our concepts and activities and I'm currently catching up with an introduction flyer for the MSCC that I'm going to send out to all those contacts via mail. It would be great to have more craftsmen as well as professional support on board. Some pictures from the event MSCC: Fantastic outlook for the near future. Announcements were made on Big data, nanotechnology, and space control centre in Mauritius. Interesting! MSCC: The lobby area was cramped with students. Great way to exchange and network. Good luck to all candidates! Passing the relay staff to... I recommend you to continue to read about the first Career & IT Fair on Ish's blog. He has a great summary and more details on those two days of IT activities than I have. Thanks and feel free to leave a comment (or two)... 

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  • A deadlock was detected while trying to lock variables in SSIS

    Error: 0xC001405C at SQL Log Status: A deadlock was detected while trying to lock variables "User::RowCount" for read/write access. A lock cannot be acquired after 16 attempts. The locks timed out. Have you ever considered variable locking when building your SSIS packages? I expect many people haven’t just because most of the time you never see an error like the one above. I’ll try and explain a few key concepts about variable locking and hopefully you never will see that error. First of all, what is all this variable locking all about? Put simply SSIS variables have to be locked before they can be accessed, and then of course unlocked once you have finished with them. This is baked into SSIS, presumably to reduce the risk of race conditions, but with that comes some additional overhead in that you need to be careful to avoid lock conflicts in some scenarios. The most obvious place you will come across any hint of locking (no pun intended) is the Script Task or Script Component with their ReadOnlyVariables and ReadWriteVariables properties. These two properties allow you to enter lists of variables to be used within the task, or to put it another way, these lists of variables to be locked, so that they are available within the task. During the task pre-execute phase the variables and locked, you then use them during the execute phase when you code is run, and then unlocked for you during the post-execute phase. So by entering the variable names in one of the two list, the locking is taken care of for you, and you just read and write to the Dts.Variables collection that is exposed in the task for the purpose. As you can see in the image above, the variable PackageInt is specified, which means when I write the code inside that task I don’t have to worry about locking at all, as shown below. public void Main() { // Set the variable value to something new Dts.Variables["PackageInt"].Value = 199; // Raise an event so we can play in the event handler bool fireAgain = true; Dts.Events.FireInformation(0, "Script Task Code", "This is the script task raising an event.", null, 0, ref fireAgain); Dts.TaskResult = (int)ScriptResults.Success; } As you can see as well as accessing the variable, hassle free, I also raise an event. Now consider a scenario where I have an event hander as well as shown below. Now what if my event handler uses tries to use the same variable as well? Well obviously for the point of this post, it fails with the error quoted previously. The reason why is clearly illustrated if you consider the following sequence of events. Package execution starts Script Task in Control Flow starts Script Task in Control Flow locks the PackageInt variable as specified in the ReadWriteVariables property Script Task in Control Flow executes script, and the On Information event is raised The On Information event handler starts Script Task in On Information event handler starts Script Task in On Information event handler attempts to lock the PackageInt variable (for either read or write it doesn’t matter), but will fail because the variable is already locked. The problem is caused by the event handler task trying to use a variable that is already locked by the task in Control Flow. Events are always raised synchronously, therefore the task in Control Flow that is raising the event will not regain control until the event handler has completed, so we really do have un-resolvable locking conflict, better known as a deadlock. In this scenario we can easily resolve the problem by managing the variable locking explicitly in code, so no need to specify anything for the ReadOnlyVariables and ReadWriteVariables properties. public void Main() { // Set the variable value to something new, with explicit lock control Variables lockedVariables = null; Dts.VariableDispenser.LockOneForWrite("PackageInt", ref lockedVariables); lockedVariables["PackageInt"].Value = 199; lockedVariables.Unlock(); // Raise an event so we can play in the event handler bool fireAgain = true; Dts.Events.FireInformation(0, "Script Task Code", "This is the script task raising an event.", null, 0, ref fireAgain); Dts.TaskResult = (int)ScriptResults.Success; } Now the package will execute successfully because the variable lock has already been released by the time the event is raised, so no conflict occurs. For those of you with a SQL Engine background this should all sound strangely familiar, and boils down to getting in and out as fast as you can to reduce the risk of lock contention, be that SQL pages or SSIS variables. Unfortunately we cannot always manage the locking ourselves. The Execute SQL Task is very often used in conjunction with variables, either to pass in parameter values or get results out. Either way the task will manage the locking for you, and will fail when it cannot lock the variables it requires. The scenario outlined above is clear cut deadlock scenario, both parties are waiting on each other, so it is un-resolvable. The mechanism used within SSIS isn’t actually that clever, and whilst the message says it is a deadlock, it really just means it tried a few times, and then gave up. The last part of the error message is actually the most accurate in terms of the failure, A lock cannot be acquired after 16 attempts. The locks timed out.  Now this may come across as a recommendation to always manage locking manually in the Script Task or Script Component yourself, but I think that would be an overreaction. It is more of a reminder to be aware that in high concurrency scenarios, especially when sharing variables across multiple objects, locking is important design consideration. Update – Make sure you don’t try and use explicit locking as well as leaving the variable names in the ReadOnlyVariables and ReadWriteVariables lock lists otherwise you’ll get the deadlock error, you cannot lock a variable twice!

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  • Organization &amp; Architecture UNISA Studies &ndash; Chap 5

    - by MarkPearl
    Learning Outcomes Describe the operation of a memory cell Explain the difference between DRAM and SRAM Discuss the different types of ROM Explain the concepts of a hard failure and a soft error respectively Describe SDRAM organization Semiconductor Main Memory The two traditional forms of RAM used in computers are DRAM and SRAM DRAM (Dynamic RAM) Divided into two technologies… Dynamic Static Dynamic RAM is made with cells that store data as charge on capacitors. The presence or absence of charge in a capacitor is interpreted as a binary 1 or 0. Because capacitors have natural tendency to discharge, dynamic RAM requires periodic charge refreshing to maintain data storage. The term dynamic refers to the tendency of the stored charge to leak away, even with power continuously applied. Although the DRAM cell is used to store a single bit (0 or 1), it is essentially an analogue device. The capacitor can store any charge value within a range, a threshold value determines whether the charge is interpreted as a 1 or 0. SRAM (Static RAM) SRAM is a digital device that uses the same logic elements used in the processor. In SRAM, binary values are stored using traditional flip flop logic configurations. SRAM will hold its data as along as power is supplied to it. Unlike DRAM, no refresh is required to retain data. SRAM vs. DRAM DRAM is simpler and smaller than SRAM. Thus it is more dense and less expensive than SRAM. The cost of the refreshing circuitry for DRAM needs to be considered, but if the machine requires a large amount of memory, DRAM turns out to be cheaper than SRAM. SRAMS are somewhat faster than DRAM, thus SRAM is generally used for cache memory and DRAM is used for main memory. Types of ROM Read Only Memory (ROM) contains a permanent pattern of data that cannot be changed. ROM is non volatile meaning no power source is required to maintain the bit values in memory. While it is possible to read a ROM, it is not possible to write new data into it. An important application of ROM is microprogramming, other applications include library subroutines for frequently wanted functions, System programs, Function tables. A ROM is created like any other integrated circuit chip, with the data actually wired into the chip as part of the fabrication process. To reduce costs of fabrication, we have PROMS. PROMS are… Written only once Non-volatile Written after fabrication Another variation of ROM is the read-mostly memory, which is useful for applications in which read operations are far more frequent than write operations, but for which non volatile storage is required. There are three common forms of read-mostly memory, namely… EPROM EEPROM Flash memory Error Correction Semiconductor memory is subject to errors, which can be classed into two categories… Hard failure – Permanent physical defect so that the memory cell or cells cannot reliably store data Soft failure – Random error that alters the contents of one or more memory cells without damaging the memory (common cause includes power supply issues, etc.) Most modern main memory systems include logic for both detecting and correcting errors. Error detection works as follows… When data is to be read into memory, a calculation is performed on the data to produce a code Both the code and the data are stored When the previously stored word is read out, the code is used to detect and possibly correct errors The error checking provides one of 3 possible results… No errors are detected – the fetched data bits are sent out An error is detected, and it is possible to correct the error. The data bits plus error correction bits are fed into a corrector, which produces a corrected set of bits to be sent out An error is detected, but it is not possible to correct it. This condition is reported Hamming Code See wiki for detailed explanation. We will probably need to know how to do a hemming code – refer to the textbook (pg. 188 – 189) Advanced DRAM organization One of the most critical system bottlenecks when using high-performance processors is the interface to main memory. This interface is the most important pathway in the entire computer system. The basic building block of main memory remains the DRAM chip. In recent years a number of enhancements to the basic DRAM architecture have been explored, and some of these are now on the market including… SDRAM (Synchronous DRAM) DDR-DRAM RDRAM SDRAM (Synchronous DRAM) SDRAM exchanges data with the processor synchronized to an external clock signal and running at the full speed of the processor/memory bus without imposing wait states. SDRAM employs a burst mode to eliminate the address setup time and row and column line precharge time after the first access In burst mode a series of data bits can be clocked out rapidly after the first bit has been accessed SDRAM has a multiple bank internal architecture that improves opportunities for on chip parallelism SDRAM performs best when it is transferring large blocks of data serially There is now an enhanced version of SDRAM known as double data rate SDRAM or DDR-SDRAM that overcomes the once-per-cycle limitation of SDRAM

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  • Goals for 2010 Retrospective

    - by Brian Jackett
    As we approach the end of 2010 I’d like to take a  few minutes to reflect back on this past year and revisit the goals that I set for myself at the beginning of the year (click here to see those goals).  I feel it is important to track your goals not only to see if you accomplished them but also to see what new directions in life you pursued.  Once we enter into 2011 I’ll follow up with a new post on goals for the new year. Professional Blog – This year I intended to write at least 2 posts a month.  Looking back I far surpassed that goal by writing 47 posts (this one being my 48th).  As with many things in life, quantity does not mean quality.  A good example is a number of my posts announcing upcoming speaking engagements and providing links to presentation slides and scripts.  That aside, I like to at least keep content relatively fresh on this blog  which I was able to accomplish.  At the same time I’ve gotten much more comfortable in my blogging style and it has become much easier to write. Speaking – I didn’t define a clear goal for speaking engagements, but had a rough idea of wanting to speak at 2-3 events.  Once again I far exceeded that number by speaking at 10 separate events and delivering 12+ presentations.  I’m very thankful for all of the opportunities that I was given and all of the wonderful people I have met as a result. Volunteering – This year I intended to help out with the COSPUG (now Buckeye SPUG) steering committee and Stir Trek conference.  I fulfilled both goals and as well as taking on lead organizer duties for the first ever SharePoint Saturday Columbus.  Each of these events and groups turned out to be successful and I was glad to be a part of them all.  I look forward to continuing to volunteer with each next year in some capacity. Android Development – My goal for getting into Android development was a late addition, but one I didn’t necessarily fulfill.  I spent a couple nights downloading the tools, configuring my environment, and going through some “simple” tutorials.  I say “simple” because in my opinion the tutorials were not laid out very well, took a long time to get running properly, and confused me more than helped.  After about a week I was frustrated with the process and didn’t think it was a good use of my time.  On a side note, I’ve dabbled in Windows Phone 7 development over the past few months and have been very excited by how easy and intuitive it was to get started and develop some proof of concepts. Personal Getting in Shape – I had intended to play on recreational sports leagues and work out on a semi-regular basis.  For the most part I fulfilled this goal by playing on various softball and volleyball leagues as well as using the gym.  At the same time I had some major setbacks.  In the spring I badly sprained my ankle and got hit in the knee with a softball which kept me inactive for almost 2 months.  More recently I broke my knuckle (click here to read about it) which I am still recovering from. Volunteering – On the volunteering front I kept my commitments at my parish’s high school youth group.  As for other volunteering opportunities I got involved with a great organization called Columbus Gives Back (website).  I’ve volunteered with them a few times and really enjoy their goal to provide opportunities to people with busy schedules.  They  offer a variety of events typically after work hours and spread out around Columbus with no set commitments on time you need to put in.  If you have the time or motivation I highly recommend them. House/Condo – I had been thinking of buying a house or condo this past summer, but decided to extend my apartment lease for another year instead.  I have begun the search for a place in the past few weeks and am excited begin the process of owning a home. Conclusion     This year I was able to set and achieve many of my goals.  For next year I’ll try to put more specific numbers to all of my goals.  If any of you readers set goals for 2011 feel free to send me a link as I’d love to see what you are aiming to accomplish.  Have a great end of 2010 and best wishes for the start of 2011!       -Frog Out

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  • Principles of an extensible data proxy

    - by Wesley
    There is a growing industry now with more than 30 companies playing in the Backend-As-A-Service (BaaS) market. The principle is simple: give companies a secure way of exposing data housed on premises and behind the firewall publicly. This can include database data, as well as Legacy PC data through established connectors; SAP for example provides a connector for transacting with their legacy systems. Early attempts were fixed providers for specific systems like SAP, IBM or Oracle, but the new breed is extensible, allowing Channel Partners and Consultants to build robust integration applications that can consume whatever data sources the client wants to expose. I just happen to be close to finishing a Cloud Based HTML5 application platform that provides robust integration services, and I would like to break ground on an extensible data proxy to complete the system. From what I can gather, I need to provide either an installable web service of some kind, or a Cloud service which the client can configure with VPN for interactions. Then I can build in connectors, which can be activated with a service account, and expose those transactions via web services of some kind (JSON, SOAP, etc). I can also provide a framework that allows people to build in their own connectors, and use some kind of schema to hook those connectors into the proxy. The end result is some kind of public facing web service that could securely be consumed by applications to show data through HTML5 on any device. My gut is, this isn't as hard as it sounds. Almost all of the 30+ companies (With more popping up almost weekly) have all come into existence in the last 18 months or so, which tells me either the root technology, or the skillset to create the technology is in abundance right now. Where should I start on this? Are there some open source projects I can leverage? A specific group of developers I can hire? I'm confident someone here can set me on the right path and save me some time. You don't see this many companies spring up this rapidly if they are all starting from scratch with proprietary technology. The Register: WTF is BaaS One Minute Video from Kony on their BaaS

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  • UppercuT v1.0 and 1.1&ndash;Linux (Mono), Multi-targeting, SemVer, Nitriq and Obfuscation, oh my!

    - by Robz / Fervent Coder
    Recently UppercuT (UC) quietly released version 1 (in August). I’m pretty happy with where we are, although I think it’s a few months later than I originally planned. I’m glad I held it back, it gave me some more time to think about some things a little more and also the opportunity to receive a patch for running builds with UC on Linux. We also released v1.1 very recently (December). UppercuT v1 Builds On Linux Perhaps the most significant changes to UC going v1 is that it now supports builds on Linux using Mono! This is thanks mostly to Svein Ackenhausen for the patches and working with me on getting it all working while not breaking the windows builds!  This means you can use mono on Windows or Linux. Notice the shell files to execute with Linux that come as part of UC now. Multi-Targeting Perhaps one of the hardest things to do that requires an automated build is multi-targeting. At v1 this is early, and possibly prone to some issues, but available.  We believe in making everything stupid simple, so it’s as simple as adding a comma to the microsoft.framework property. i.e. “net-3.5, net-4.0” to suddenly produce both framework builds. When you build, this is what you get (if you meet each framework’s requirements): At this time you have to let UC override the build location (as it does by default) or this will not work.  Semantic Versioning By now many of you have been using UppercuT for awhile and have watched how we have done versioning. Many of you who use git already know we put the revision hash in the informational/product version as the last octet. At v1, UppercuT has adopted the semantic versioning scheme. What does that mean? This is a short read, but a good one: http://SemVer.org SemVer (Semantic Versioning) is really using versioning what it was meant for. You have three octets. Major.Minor.Patch as in 1.1.0.  UC will use three different versioning concepts, one for the assembly version, one for the file version, and one for the product version. All versions - The first three octects of the version are owned by SemVer. Major.Minor.Patch i.e.: 1.1.0 Assembly Version - The assembly version would much closer follow SemVer. Last digit is always 0. Major.Minor.Patch.0 i.e: 1.1.0.0 File Version - The file version occupies the build number as the last digit. Major.Minor.Patch.Build i.e.: 1.1.0.2650 Product/Informational Version - The last octect of your product/informational version is the source control revision/hash. Major.Minor.Patch.RevisionOrHash i.e. (TFS/SVN): 1.1.0.235 i.e. (Git/HG): 1.1.0.a45ace4346adef0 SemVer is not on by default, the passive versioning scheme is still in effect. Notice that version.use_semanticversioning has been added to the UppercuT.config file (and version.patch in support of the third octet): Gems Support Gems support was added at v1. This will probably be deprecated as some point once there is an announced sunset for Nu v1. Application gems may keep it around since there is no alternative for that yet though (CoApp would be a possible replacement). Nitriq Support Nitriq is a code analysis tool like NDepend. It’s built by Mr. Jon von Gillern. It uses LINQ query language, so you can use a familiar idiom when analyzing your code base. It’s a pretty awesome tool that has a free version for those looking to do code analysis! To use Nitriq with UC, you are going to need the console edition.  To take advantage of Nitriq, you just need to update the location of Nitriq in the config: Then add the nitriq project files at the root of your source. Please refer to the Nitriq documentation on how these are created. UppercuT v1.1 Obfuscation One thing I started looking into was an easy way to obfuscate my code. I came across EazFuscator, which is both free and awesome. Plus the GUI for it is super simple to use. How do you make obfuscation even easier? Make it a convention and a configurable property in the UC config file! And the code gets obfuscated! Closing Definitely get out and look at the new release. It contains lots of chocolaty (sp?) goodness. And remember, the upgrade path is almost as simple as drag and drop!

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  • When is my View too smart?

    - by Kyle Burns
    In this posting, I will discuss the motivation behind keeping View code as thin as possible when using patterns such as MVC, MVVM, and MVP.  Once the motivation is identified, I will examine some ways to determine whether a View contains logic that belongs in another part of the application.  While the concepts that I will discuss are applicable to most any pattern which favors a thin View, any concrete examples that I present will center on ASP.NET MVC. Design patterns that include a Model, a View, and other components such as a Controller, ViewModel, or Presenter are not new to application development.  These patterns have, in fact, been around since the early days of building applications with graphical interfaces.  The reason that these patterns emerged is simple – the code running closest to the user tends to be littered with logic and library calls that center around implementation details of showing and manipulating user interface widgets and when this type of code is interspersed with application domain logic it becomes difficult to understand and much more difficult to adequately test.  By removing domain logic from the View, we ensure that the View has a single responsibility of drawing the screen which, in turn, makes our application easier to understand and maintain. I was recently asked to take a look at an ASP.NET MVC View because the developer reviewing it thought that it possibly had too much going on in the view.  I looked at the .CSHTML file and the first thing that occurred to me was that it began with 40 lines of code declaring member variables and performing the necessary calculations to populate these variables, which were later either output directly to the page or used to control some conditional rendering action (such as adding a class name to an HTML element or not rendering another element at all).  This exhibited both of what I consider the primary heuristics (or code smells) indicating that the View is too smart: Member variables – in general, variables in View code are an indication that the Model to which the View is being bound is not sufficient for the needs of the View and that the View has had to augment that Model.  Notable exceptions to this guideline include variables used to hold information specifically related to rendering (such as a dynamically determined CSS class name or the depth within a recursive structure for indentation purposes) and variables which are used to facilitate looping through collections while binding. Arithmetic – as with member variables, the presence of arithmetic operators within View code are an indication that the Model servicing the View is insufficient for its needs.  For example, if the Model represents a line item in a sales order, it might seem perfectly natural to “normalize” the Model by storing the quantity and unit price in the Model and multiply these within the View to show the line total.  While this does seem natural, it introduces a business rule to the View code and makes it impossible to test that the rounding of the result meets the requirement of the business without executing the View.  Within View code, arithmetic should only be used for activities such as incrementing loop counters and calculating element widths. In addition to the two characteristics of a “Smart View” that I’ve discussed already, this View also exhibited another heuristic that commonly indicates to me the need to refactor a View and make it a bit less smart.  That characteristic is the existence of Boolean logic that either does not work directly with properties of the Model or works with too many properties of the Model.  Consider the following code and consider how logic that does not work directly with properties of the Model is just another form of the “member variable” heuristic covered earlier: @if(DateTime.Now.Hour < 12) {     <div>Good Morning!</div> } else {     <div>Greetings</div> } This code performs business logic to determine whether it is morning.  A possible refactoring would be to add an IsMorning property to the Model, but in this particular case there is enough similarity between the branches that the entire branching structure could be collapsed by adding a Greeting property to the Model and using it similarly to the following: <div>@Model.Greeting</div> Now let’s look at some complex logic around multiple Model properties: @if (ModelPageNumber + Model.NumbersToDisplay == Model.PageCount         || (Model.PageCount != Model.CurrentPage             && !Model.DisplayValues.Contains(Model.PageCount))) {     <div>There's more to see!</div> } In this scenario, not only is the View code difficult to read (you shouldn’t have to play “human compiler” to determine the purpose of the code), but it also complex enough to be at risk for logical errors that cannot be detected without executing the View.  Conditional logic that requires more than a single logical operator should be looked at more closely to determine whether the condition should be evaluated elsewhere and exposed as a single property of the Model.  Moving the logic above outside of the View and exposing a new Model property would simplify the View code to: @if(Model.HasMoreToSee) {     <div>There’s more to see!</div> } In this posting I have briefly discussed some of the more prominent heuristics that indicate a need to push code from the View into other pieces of the application.  You should now be able to recognize these symptoms when building or maintaining Views (or the Models that support them) in your applications.

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  • MVVM - how to make creating viewmodels at runtime less painfull

    - by Mr Happy
    I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painfull. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genious since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use an DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an indepth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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