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• SQL Server and Hyper-V Dynamic Memory - Part 1

  - by SQLOS Team

  SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• SQL SERVER – What is Page Life Expectancy (PLE) Counter

  - by pinaldave

  During performance tuning consultation there are plenty of counters and values, I often come across. Today we will quickly talk about Page Life Expectancy counter, which is commonly known as PLE as well. You can find the value of the PLE by running following query. SELECT [object_name], [counter_name], [cntr_value] FROM sys.dm_os_performance_counters WHERE [object_name] LIKE '%Manager%' AND [counter_name] = 'Page life expectancy' The recommended value of the PLE counter is 300 seconds. I have seen on busy system this value to be as low as even 45 seconds and on unused system as high as 1250 seconds. Page Life Expectancy is number of seconds a page will stay in the buffer pool without references. In simple words, if your page stays longer in the buffer pool (area of the memory cache) your PLE is higher, leading to higher performance as every time request comes there are chances it may find its data in the cache itself instead of going to hard drive to read the data. Now check your system and post back what is this counter value for you during various time of the day. Is this counter any way relates to performance issues for your system? Note: There are various other counters which are important to discuss during the performance tuning and this counter is not everything. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL Server and Hyper-V Dynamic Memory - Part 1

  - by SQLOS Team

  SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• Getting Started with Employee Info Starter Kit (v4.0.0)

  - by joycsharp

  The new release of Employee Info Starter Kit contains lots of exciting features available in Visual Studio 2010 and .NET 4.0. To get started with the new version, you will need less than 5 minutes. Minimum System Requirements Before getting started, please make sure you have installed Visual Studio 2010 RC (or higher) and Sql Server 2005 Express edition (or higher installed on your machine. Running the Starter Kit for First Time 1. Download the starter kit 4.0.0 version form here and extract it. 2. Go to <extraction folder>\Source\Eisk.Solution and click the solution file 3. From the solution explorer, right click the “Eisk.Web” web site project node and select “Set as Startup Project” and hit Ctrl + F5   4. You will be prompted to install database, just follow the instruction. That’s it! You are ready to use this starter kit. Running the Tests Employee Info Starter Kit contains a infrastructure for Integration and Unit Testing, by utilizing cool test tools in Visual Studio 2010. Once you complete the steps, mentioned above, take a minute to run the test cases on the fly. 1. From the solution explorer, to go “Solution Items\e-i-s-k-2010.vsmdi” and click it. You will see the available Tests in the Visual Studio Test Lists. Select all, except the “Load Tests” node (since Load Tests takes a bit time) 2. Click “Run Checked Tests” control from the upper left corner. You will see the tests running and finally the status of the tests, which indicates the current health of you application from different scenarios. Technorati Tags: asp.net,architecture,starter kit,employee info starter kit,visual studio 2010,.net 4.0,entity framework

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• Getting Started with Employee Info Starter Kit (v4.0.0)

  - by Mohammad Ashraful Alam

  The new release of Employee Info Starter Kit contains lots of exciting features available in Visual Studio 2010 and .NET 4.0. To get started with the new version, you will need less than 5 minutes. Minimum System Requirements Before getting started, please make sure you have installed Visual Studio 2010 RC (or higher) and Sql Server 2005 Express edition (or higher installed on your machine. Running the Starter Kit for First Time 1. Download the starter kit 4.0.0 version form here and extract it. 2. Go to <extraction folder>\Source\Eisk.Solution and click the solution file 3. From the solution explorer, right click the “Eisk.Web” web site project node and select “Set as Startup Project” and hit Ctrl + F5   4. You will be prompted to install database, just follow the instruction. That’s it! You are ready to use this starter kit. Running the Tests Employee Info Starter Kit contains a infrastructure for Integration and Unit Testing, by utilizing cool test tools in Visual Studio 2010. Once you complete the steps, mentioned above, take a minute to run the test cases on the fly. 1. From the solution explorer, to go “Solution Items\e-i-s-k-2010.vsmdi” and click it. You will see the available Tests in the Visual Studio Test Lists. Select all, except the “Load Tests” node (since Load Tests takes a bit time) 2. Click “Run Checked Tests” control from the upper left corner. You will see the tests running and finally the status of the tests, which indicates the current health of you application from different scenarios. Technorati Tags: asp.net,architecture,starter kit,employee info starter kit,visual studio 2010,.net 4.0,entity framework

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• LAMP Stack Versioning -- Is there a website or version tracker source to help suggest the right versions of each part of a platform stack?

  - by Chris Adragna

  Taken singly, it's easy to research versions and compatibility. Version information is readily available on each single part of a platform stack, such as MySQL. You can find out the latest version, stable version, and sometimes even the percentage of people adopting it by version (personally, I like seeing numbers on adoption rates). However, when trying to find the best possible mix of versions, I have a harder time. For example, "if you're using MySQL 5.5, you'll need PHP version XX or higher." It gets even more difficult to mitigate when you throw higher level platforms into the mix such as Drupal, Joomla, etc. I do consider "wizard" like installers to be beneficial, such as the Bitnami installers. However, I always wonder if those solutions cater more to the least common denominator -- be all to many -- and as such, I think I'd be better to install things on my own. Such solutions do seem kind of slow to adopt new versions, slower than necessary, I suspect. Is there a website or tool that consolidates versioning data in order to help a webmaster choose which versions to deploy or which upgrades to install, in consideration of all the other parts of the stack?

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• 2.5D game development

  - by ne5tebiu

  2.5D ("two-and-a-half-dimensional"), 3/4 perspective and pseudo-3D are terms used to describe either: graphical projections and techniques which cause a series of images or scenes to fake or appear to be three-dimensional (3D) when in fact they are not, or gameplay in an otherwise three-dimensional video game that is restricted to a two-dimensional plane. (Information taken from Wikipedia.org) I have a question based on 2.5D game development. As stated before, 2.5D uses graphical projections and techniques to make fake 3d or a gameplay restricted to a two-dimensional plane. A good example is a TQ Digital made game: Zero Online (screenshot) the whole map is made of 2d images and only NPCs and players are 3d. The maps were drawn manually by hand without any 3d software rendering. As I'm playing the game I feel like I'm going from a lower part of the map (ground) to a higher one (some metal platform) and it feels like I'm moving in 3 dimensions. But when I look closely, I see that the player size didn't change and the shadow too but I'm still feeling like I'm somehow higher then before (I had rendered a simple map myself that I made in 3dmax but it didn't quite give the result I wanted). How to accomplish such an effect?

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• .Net to Oracle Connectivity using ODBC .NET

  - by SAMIR BHOGAYTA

  You can use the new ODBC .NET Data Provider that works with the ODBC Oracle7.x driver or higher. You need to have MDAC 2.6 or later installed and then download ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?url=/code/sample.asp?url=/msdn-files/027/001/668/msdncompositedoc.xml&frame=true. MDAC (Microsoft Data Access Component) 2.7 contains core component, including the Microsoft SQL server and Oracle OLE Database provider and ODBC driver. Insta ...You can use the new ODBC .NET Data Provider that works with the ODBC Oracle7.x driver or higher. You need to have MDAC 2.6 or later installed and then download ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?url=/code/sample.asp?url=/msdn-files/027/001/668/msdncompositedoc.xml&frame=true. MDAC (Microsoft Data Access Component) 2.7 contains core component, including the Microsoft SQL server and Oracle OLE Database provider and ODBC driver. Install ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?URL=/downloads/sample.asp?url=/msdn-files/027/001/943/msdncompositedoc.xml Create a DSN, using either Microsoft ODBC for Oracle or Oracle supplied Driver if the Oracle client software is loaded. here for eq. TrailDSN. While creating DSN give user name along with passward for eq. scott/tiger. using Microsoft .Data.Odbc; private void Form1_Load(object sender, System.EventArgs e) { try { OdbcConnection myconnection= new OdbcConnection ("DSN=TrialDSN"); OdbcDataAdapter myda = new OdbcDataAdapter ("Select * from EMP", myconnection); DataSet ds= new DataSet (); myda.Fill(ds, "Table"); dataGrid1.DataSource = ds ; } catch(Exception ex) { MessageBox.Show (ex.Message ); } }

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• Game physics presentation by Richard Lord, some questions

  - by Steve

  I been implementing (in XNA) the examples in this physics presentation by Richard Lord where he discusses various integration techniques. Bearing in mind that I am a newcomer to game physics (and physics in general) I have some questions. 15 slides in he shows ActionScript code for a gravity example and an animation showing a bouncing ball. The ball bounces higher and higher until it is out of control. I implemented the same in C# XNA but my ball appeared to be bouncing at a constant height. The same applies to the next example where the ball bounces lower and lower. After some experimentation I found that if I switched to a fixed timestep and then on the first iteration of Update() I set the time variable to be equal to elapsed milliseconds (16.6667) I would see the same behaviour. Doing this essentially set the framerate, velocity and acceleration to zero for the first update and introduced errors(?) into the algorithm causing the ball's velocity to increase (or decrease) over time. I think! My question is, does this make the integration method used poor? Or is it demonstrating that it is poor when used with variable timestep because you can't pass in a valid value for the first lot of calculations? (because you cannot know the framerate in advance). I will continue my research into physics but can anyone suggest a good method to get my feet wet? I would like to experiment with variable timestep, acceleration that changes over time and probably friction. Would the Time Corrected Verlet be OK for this?

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• Right-Time Retail Part 3

  - by David Dorf

  This is part three of the three-part series.  Read Part 1 and Part 2 first. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Right-Time Marketing Real-time isn’t just about executing faster; it extends to interactions with customers as well. As an industry, we’ve spent many years analyzing all the data that’s been collected. Yes, that data has been invaluable in helping us make better decisions like where to open new stores, how to assort those stores, and how to price our products. But the recent advances in technology are now making it possible to analyze and deliver that data very quickly… fast enough to impact a potential sale in near real-time. Let me give you two examples. Salesmen in car dealerships get pretty good at sizing people up. When a potential customer walks in the door, it doesn’t take long for the salesman to figure out the revenue at stake. Is this person a real buyer, or just looking for a fun test drive? Will this person buy today or three months from now? Will this person opt for the expensive packages, or go bare bones? While the salesman certainly asks some leading questions, much of information is discerned through body language. But body language doesn’t translate very well over the web. Eloqua, which was acquired by Oracle earlier this year, reads internet body language. By tracking the behavior of the people visiting your web site, Eloqua categorizes visitors based on their propensity to buy. While Eloqua’s roots have been in B2B, we’ve been looking at leveraging the technology with ATG to target B2C. Knowing what sites were previously visited, how often the customer has been to your site recently, and how long they’ve spent searching can help understand where the customer is in their purchase journey. And knowing that bit of information may be enough to help close the deal with a real-time offer, follow-up email, or online customer service pop-up. This isn’t so different from the days gone by when the clerk behind the counter of the corner store noticed you were lingering in a particular aisle, so he walked over to help you compare two products and close the sale. You appreciated the personalized service, and he knew the value of the long-term relationship. Move that same concept into the digital world and you have Oracle’s CX Suite, a cloud-based offering of end-to-end customer experience tools, assembled primarily from acquisitions. Those tools are Oracle Marketing (Eloqua), Oracle Commerce (ATG, Endeca), Oracle Sales (Oracle CRM On Demand), Oracle Service (RightNow), Oracle Social (Collective Intellect, Vitrue, Involver), and Oracle Content (Fatwire). We are providing the glue that binds the CIO and CMO together to unleash synergies that drive the top-line higher, and by virtue of the cloud-approach, keep costs at bay. My second example of real-time marketing takes place in the store but leverages the concepts of Web marketing. In 1962 the decline of personalized service in retail began. Anyone know the significance of that year? That’s when Target, K-Mart, and Walmart each opened their first stores, and over the succeeding years the industry chose scale over personal service. No longer were you known as “Jane with the snotty kid so make sure we check her out fast,” but you suddenly became “time-starved female age 20-30 with kids.” I’m not saying that was a bad thing – it was the right thing for our industry at the time, and it enabled a huge amount of growth, cheaper prices, and more variety of products. But scale alone is no longer good enough. Today’s sophisticated consumer demands scale, experience, and personal attention. To some extent we’ve delivered that on websites via the magic of cookies, your willingness to log in, and sophisticated data analytics. What store manager wouldn’t love a report detailing all the visitors to his store, where they came from, and which products that examined? People trackers are getting more sophisticated, incorporating infrared, video analytics, and even face recognition. (Next time you walk in front on a mannequin, don’t be surprised if it’s looking back.) But the ultimate marketing conduit is the mobile phone. Since each mobile phone emits a unique number on WiFi networks, it becomes the cookie of the physical world. Assuming congress keeps privacy safeguards reasonable, we’ll have a win-win situation for both retailers and consumers. Retailers get to know more about the consumer’s purchase journey, and consumers get higher levels of service with the retailer. When I call my bank, a couple things happen before the call is connected. A reverse look-up on my phone number identifies me so my accounts can be retrieved from Siebel CRM. Then the system anticipates why I’m calling based on recent transactions. In this example, it sees that I was just charged a foreign currency fee, so it assumes that’s the reason I’m calling. It puts all the relevant information on the customer service rep’s screen as it connects the call. When I complain about the fee, the rep immediately sees I’m a great customer and I travel lots, so she suggests switching me to their traveler’s card that doesn’t have foreign transaction fees. That technology is powered by a product called Oracle Real-Time Decisions, a rules engine built to execute very quickly, basically in the time it takes the phone to ring once. So let’s combine the power of that product with our new-found mobile cookie and provide contextual customer interactions in real-time. Our first opportunity comes when a customer crosses a pre-defined geo-fence, typically a boundary around the store. Context is the key to our interaction: that’s the customer (known or anonymous), the time of day and day of week, and location. Thomas near the downtown store on a Wednesday at noon means he’s heading to lunch. If he were near the mall location on a Saturday morning, that’s a completely different context. But on his way to lunch, we’ll let Thomas know that we’ve got a new shipment of ASICS running shoes on display with a simple text message. We used the context to look-up Thomas’ past purchases and understood he was an avid runner. We used the fact that this was lunchtime to select the type of message, in this case an informational message instead of an offer. Thomas enters the store, phone in hand, and walks to the shoe department. He scans one of the new ASICS shoes using the convenient QR Codes we provided on the shelf-tags, but then he starts scanning low-end Nikes. Each scan is another opportunity to both learn from Thomas and potentially interact via another message. Since he historically buys low-end Nikes and keeps scanning them, he’s likely falling back into his old ways. Our marketing rules are currently set to move loyal customer to higher margin products. We could have set the dials to increase visit frequency, move overstocked items, increase basket size, or many other settings, but today we are trying to move Thomas to higher-margin products. We send Thomas another text message, this time it’s a personalized offer for 10% off ASICS good for 24 hours. Offering him a discount on Nikes would be throwing margin away since he buys those anyway. We are using our marketing dollars to change behavior that increases the long-term value of Thomas. He decides to buy the ASICS and scans the discount code on his phone at checkout. Checkout is yet another opportunity to interact with Thomas, so the transaction is sent back to Oracle RTD for evaluation. Since Thomas didn’t buy anything with the shoes, we’ll print a bounce-back coupon on the receipt offering 30% off ASICS socks if he returns within seven days. We have successfully started moving Thomas from low-margin to high-margin products. In both of these marketing scenarios, we are able to leverage data in near real-time to decide how best to interact with the customer and lead to an increase in the lifetime value of the customer. The key here is acting at the moment the customer shows interest using the context of the situation. We aren’t pushing random products at haphazard times. We are tailoring the marketing to be very specific to this customer, and it’s the technology that allows this to happen in near real-time. Conclusion As we enable more right-time integrations and interactions, retailers will begin to offer increased service to their customers. Localized and personalized service at scale will drive loyalty and lead to meaningful revenue growth for the retailers that execute well. Our industry needs to support Commerce Anywhere…and commerce anytime as well.

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• NRF Week - Disney Store Tour

  - by sarah.taylor(at)oracle.com

  Disney has created a real buzz at this year's NRF event. Yesterday morning we began the Oracle Retail Exchange program with a visit to the flagship Disney store in Times Square. Additionally Oracle made a key announcement with Disney  on Oracle Retail's Point of Sale implementation in 330 stores worldwide. Today   Disney's Steve Finney gave a super session on The Magic of Disney at the NRF Big Show. We also saw Disney making an exclusive news announcement about their plans for Global store openings at the Oracle trade show stand - with a little help from Mickey and Minnie Mouse. Disney Stores have been entirely reinvented since the company in 2008 took ownership after previously franchising the retail arm of the business. They have subsequently been a strong Oracle partner and technology has played a key role in their re imagination of the store environment. The new Imagination stores have a 20% higher footfall and margins are up 25%. The Disney brand is synonymous with magical and memorable experiences for children of all ages. The company is achieving a unique retail experience that delights children and shareholders alike! Technology is a key pillar in helping to deliver on both a strong operating model and a unique customer experience - the best thirty minutes in a child's day is their aim. Steve Finney this morning said their technology has to be as reliable as a theme park ride. Store experiences are much more enjoyable when there are short waiting times and children can interact with their favourite characters through magic mirrors, mobile point of sale, touch screens and custom animations that are digitally transmitted to stores globally. The Oracle Retail Point of Sale with iPad touch screens reduces check out times, stores customer data, ensures that promotions are delivered accurately and reduces losses. This means higher levels of guest conversion, increased availability and convenience for customers who want to check availability at other locations. Disney is a pioneer. At NRF's 100th show, we had the privilege of learning from a retailer using technology as a creative force to drive their business forward.

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• Why are SW engineering interviews disproportionately difficult?

  - by stackoverflowuser2010

  First, some background on me. I have a PhD in CS and have had jobs both as a software engineer and as an R&D research scientist, both at Very Large Corporations You Know Very Well. I recently changed jobs and interviewed for both types of jobs (as I have done in the past). My observation: SW engineer job interviews are way, way disproportionately more difficult than CS researcher job interviews, but the researcher job is higher paying, more competitive, more rewarding, more interesting, and has a higher upside. Here's a typical interview loop for researcher: Phone interview to see if my research is in alignment with the lab's researcher In-person, give presentation on my recent research for one hour (which represents maybe 9 month's worth of work), answer questions In-person one-on-one interviews with about 5 researchers, where they ask me very reasonable questions on my work/publications/patents, including: technical questions, where my work fits into related work, and how I can extend my work to new areas Here's a typical interview loop for SW engineer: Phone interview where I'm asked algorithm questions and maybe do some coding. Pretty standard. In-person interviews at the whiteboard where they drill the F*** out of you on esoteric C++ minutia (e.g. how does a polymorphic virtual function call work), algorithms (make all-pairs-shortest-path algorithm work for 1B vertices), system design (design a database load balancer), etc. This goes on for six or seven interviews. Ridiculous. Why would anyone be willing to put up with this? What is the point of asking about C++ trivia or writing code to prove yourself? Why not make the SE interview more like the researcher interview where you give a talk about what you've done? How are technical job interviews for other fields, like physics, chemistry, civil engineering, mechanical engineering?

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• Low-level GPU code and Shader Compilation

  - by ktodisco

  Bear with me, because I will raise several questions at once. I still feel, though, that overall this can be treated as one question that may be answered succinctly. I recently dove into solidifying my understanding of the assembly language, low-level memory operations, CPU structure, and program optimizations. This also sparked my interest in how higher-level shading languages, GLSL and HLSL in particular, are compiled and optimized, as well as what formats they are reduced to before machine code is generated (assuming they are not converted directly into machine code). After a bit of research into this, the best resource I've found is this presentation from ATI about the compilation of and optimizations for HLSL. I also found sample ARB assembly code. This sort of addressed my original curiosity, but it raised several other questions. The assembler code in the ATI presentation seems like it contains instructions specifically targeted for the GPU, but is this merely a hypothetical example created for the purpose of conceptual understanding, or is this code really generated during shader compilation? If so, is it possible to inspect it, or even write it in place of the higher-level syntax? My initial searches for an answer to the last question tell me that this may be disallowed, but I have not dug too deep yet. Also, along the same lines, are GLSL shader programs compiled into ARB assembly code before machine code is generated, and is it possible to write direct ARB assembly? Lastly, and perhaps what I am most interested in finding out: are there comprehensive resources on shader compilation and low-level GPU code? I have been unable to find any thus far. I ask simply because I am curious :)

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• A Multi-Channel Contact Center Can Reduce Total Cost of Ownership

  - by Tom Floodeen

  In order to remain competitive in today’s market, CRM customers need to provide feature-rich superior call center experience to their customers across all communication channels while improving their service agent productivity. They also require their call center to be deeply integrated with their CRM system; and they need to implement all this quickly, seamlessly, and without breaking the bank. Oracle’s Siebel Customer Relationship Management (CRM) is the world’s leading application suite for automated customer-facing operations for Sales and Marketing and for managing all aspects of providing service to customers. Oracle’s Contact On Demand (COD) is a world-class carrier grade hosted multi-channel contact center solution that can be deployed in days without up-front capital expenditures or integration costs. Agents can work efficiently from anywhere in the world with 360-degree views into customer interactions and real-time business intelligence. Customers gain from rapid and personalized sales and service, while organizations can dramatically reduce costs and increase revenues Oracle’s latest update of Siebel CRM now comes pre-integrated with Oracle’s Contact On Demand. This solution seamlessly runs fully-functional contact center provided by a single vendor, significantly reducing your total cost of ownership. This solution supports Siebel 7.8 and higher for Voice and Siebel 8.1 and higher for Voice and Siebel CRM Chat.  The impressive feature list of Oracle’s COD solution includes full-control CTI toolbar with Voice, Chat, and Click to Dial features.  It also includes context-sensitive screens, automated desktops, built-in IVR, Multidimensional routing, Supervisor and Quality monitoring, and Instant Provisioning. The solution also ships with Extensible Web Services interface for implementing more complex business processes. Click here to learn how to reduce complexity and total cost of ownership of your contact center. Contact Ann Singh at [email protected] for additional information.

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• Installation Problems & Antivirus

  - by Sagar Walvekar

  We have just migrated our systems from Windows to Ubuntu. We have more than 50 systems previously running Windows XP & Windows 7. After the release of 12.04 we decided to switch to Ubuntu. While we were installing Ubuntu 12.04 on Pentium 4 systems we have faced some issues. We tried it with a USB flash driver & CD. The typical configuration of the system is as follows: Pentium 4 with HT & 512 MB RAM, 40/80 GB IDE / SATA HDD. In windows there were several partitions and data on all the drives in all the systems. We have addressed this by taking backup of the C: drive on other drives & while installing Ubuntu we have just deleted & the C drive & recreated Linux partitions as follows - /root , /Boot, /Home & Swap.(in 10 GB) The problem is that the Linux gets installed without any error. However when I restart the system after the installation the system hangs in while detecting the HDD in BIOS and the system fails to start until I remove the HDD. When I installed the previous Ubuntu version it worked fine, without any hassle. Also if we install Ubuntu 12.04 on same HDD on any other higher capacity system & reconnected to old system it works fine. How can I fix this problem? Also, is there is any Antivirus which will give me real time protection on ubuntu 11 & higher versions with both 32 & 64 Bits?

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• BDD/TDD vs JAD?

  - by Jonathan Conway

  I've been proposing that my workplace implement Behavior-Driven-Development, by writing high-level specifications in a scenario format, and in such a way that one could imagine writing a test for it. I do know that working against testable specifications tends to increase developer productivity. And I can already think of several examples where this would be the case on our own project. However it's difficult to demonstrate the value of this to the business. This is because we already have a Joint Application Development (JAD) process in place, in which developers, management, user-experience and testers all get together to agree on a common set of requirements. So, they ask, why should developers work against the test-cases created by testers? These are for verification and are based on the higher-level specs created by the UX team, which the developers currently work off. This, they say, is sufficient for developers and there's no need to change how the specs are written. They seem to have a point. What is the actual benefit of BDD/TDD, if you already have a test-team who's test cases are fully compatible with the higher-level specs currently given to the developers?

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• Introducing the Industry's First Analytics Machine, Oracle Exalytics

  - by Manan Goel

  Analytics is all about gaining insights from the data for better decision making. The business press is abuzz with examples of leading organizations across the world using data-driven insights for strategic, financial and operational excellence. A recent study on “data-driven decision making” conducted by researchers at MIT and Wharton provides empirical evidence that “firms that adopt data-driven decision making have output and productivity that is 5-6% higher than the competition”. The potential payoff for firms can range from higher shareholder value to a market leadership position. However, the vision of delivering fast, interactive, insightful analytics has remained elusive for most organizations. Most enterprise IT organizations continue to struggle to deliver actionable analytics due to time-sensitive, sprawling requirements and ever tightening budgets. The issue is further exasperated by the fact that most enterprise analytics solutions require dealing with a number of hardware, software, storage and networking vendors and precious resources are wasted integrating the hardware and software components to deliver a complete analytical solution. Oracle Exalytics In-Memory Machine is the world’s first engineered system specifically designed to deliver high performance analysis, modeling and planning. Built using industry-standard hardware, market-leading business intelligence software and in-memory database technology, Oracle Exalytics is an optimized system that delivers answers to all your business questions with unmatched speed, intelligence, simplicity and manageability. Oracle Exalytics’s unmatched speed, visualizations and scalability delivers extreme performance for existing analytical and enterprise performance management applications and enables a new class of intelligent applications like Yield Management, Revenue Management, Demand Forecasting, Inventory Management, Pricing Optimization, Profitability Management, Rolling Forecast and Virtual Close etc. Requiring no application redesign, Oracle Exalytics can be deployed in existing IT environments by itself or in conjunction with Oracle Exadata and/or Oracle Exalogic to enable extreme performance and best in class user experience. Based on proven hardware, software and in-memory technology, Oracle Exalytics lowers the total cost of ownership, reduces operational risk and provides unprecedented analytical capability for workgroup, departmental and enterprise wide deployments. Click here to learn more about Oracle Exalytics.  

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• CRM Evolution 2014: Mediocrity is the New Horrible in Customer Service

  - by Tuula Fai

  "Mediocrity is the new horrible in customer service," Blair McHaney, Gold's Gym Almost everyone knows that customers' expectations have risen. But, after listening to two days of presentations at CRM Evolution, I think it’s more accurate to say that customers' expectations have skyrocketed. Fortunately, most companies have gotten the message and are taking their customer service to a higher level. For those who've been hesitant to 'boldly go where their customer service organization has not gone before,' take heart. I’ve got some statistics that will encourage you to take those first few steps. Why should I change? By engaging customers online, ancestry.com achieved a 99.5% customer satisfaction score (CSAT) while improving retention and saving millions on greater efficiency, including a 38%-50% drop in inbound calls and emails.1 By empowering employees to delight customers, Gold’s Gym achieved a 77.5% Net Promoter Score (NPS) and 22% customer churn rate. No small feat when you consider the industry averages are 40% NPS and 45% churn.2 By adapting quickly to social media, brands like Verizon have benefited from social community members spending 2.5x-10x more than average customers.3 ‘The fierce urgency of now’ is upon us in customer service. You can take your customer service to a higher level! To find out more, click here CRM Evolution Customer Service Experience Footnotes: 1. Arvindh Balakrishnan, Is Your Customer Service Modern?2. Blair McHaney, Wire Your Organization with Customer Feedback3. Becky Carroll, The Power of Communities for Improving the Service Experience and Building Advocates

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• GLSL, is it possible to offsetting vertices based on height map colour?

  - by Rob

  I am attempting to generate some terrain based upon a heightmap. I have generated a 32 x 32 grid and a corresponding height map - In my vertex shader I am trying to offset the position of the Y axis based upon the colour of the heightmap, white vertices being higher than black ones. //Vertex Shader Code #version 330 uniform mat4 modelMatrix; uniform mat4 viewMatrix; uniform mat4 projectionMatrix; uniform sampler2D heightmap; layout (location=0) in vec4 vertexPos; layout (location=1) in vec4 vertexColour; layout (location=3) in vec2 vertexTextureCoord; layout (location=4) in float offset; out vec4 fragCol; out vec4 fragPos; out vec2 fragTex; void main() { // Retreive the current pixel's colour vec4 hmColour = texture(heightmap,vertexTextureCoord); // Offset the y position by the value of current texel's colour value ? vec4 offset = vec4(vertexPos.x , vertexPos.y + hmColour.r, vertexPos.z , 1.0); // Final Position gl_Position = projectionMatrix * viewMatrix * modelMatrix * offset; // Data sent to Fragment Shader. fragCol = vertexColour; fragPos = vertexPos; fragTex = vertexTextureCoord; } However the code I have produced only creates a grid with none of the y vertices higher than any others.

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• YouTube: Promotional AgroSense Movie

  - by Geertjan

  Here's a cool YouTube promotional movie on AgroSense created by Ordina in the Netherlands. AgroSense is an open source Java system for the precision agriculture industry, which won the IT Environment Award in the Netherlands last week: If your understanding of Dutch limits your appreciation of the movie above, here's a rough translation, together with the names of the speakers in the movie: Precision agriculture, an innovative form of agriculture in which local variations in soil, crop, and atmosphere are taken into account, is the high-tech sustainable agriculture of tomorrow. The use of fertilizer, water, and energy can in this way be significantly reduced. "If, ten or twenty years from now, we are to continue having our agricultural industry in good shape, and in a continuing state of health, we'll need to register and work with data because if we want to enable crops to provide higher value, we'll need to create higher levels of transparency throughout the agriculture chain." Lenus Hamster, farmer in Nieuwolda Groningen "Industry is becoming increasingly data intensive. By combining pragmatic usefulness with innovative sustainability, AgroSense offers the Netherlands the possibility to continue being a leading player in the agrofood sector." Art Lighthart, Architect at Ordina AgroSense offers an open source solution in which all services for precision agriculture are brought together. In 2012, co-operation is being sought with organizations to make AgroSense available to around 10,000 Dutch farmers in the arable crop sector. By the way, the last sentence above implies the NetBeans Platform will be used by around 10,000 Dutch farmers.

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• Google search question, front page not showing...

  - by Catelyn

  I know this is probably a dumb question but I hope someone can give me some insight; I was ranked on Google first page of search results for "funny st patricks day shirts" but I was third from the bottom and not familiar enough with SEO, so I signed up for "Attracta" to rank higher. Big mistake. Since using Attracta, I've lost the first page and I'm now on the fourth page in that search. What I noticed is that Google is now just showing a sub-page or side page, (a link from my front page, to a page which has only a few designs in it) this is not where I would want customers to land first... but my front page is not showing in that search anymore. Obviously, the title of this side page is not geared toward that search result, so I know that's why I have the pr drop. Why is my front page not ranking over that page, though? Why is it apparently gone from that search, or so far back no one will ever find it? I need to know how to fix this quick if anyone has any advice at all for me. It's the busiest season for my website and the people who were stealing design ideas from me are all ranked higher than my site now. (I can prove this, lol) So, I'm very frustrated by that. I would be very grateful to have any advice at all as to what I can do to fix this. THANKS in advance for any advice you can offer. Catelyn

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• Performance of concurrent software on multicore processors

  - by Giorgio

  Recently I have often read that, since the trend is to build processors with multiple cores, it will be increasingly important to have programming languages that support concurrent programming in order to better exploit the parallelism offered by these processors. In this respect, certain programming paradigms or models are considered well-suited for writing robust concurrent software: Functional programming languages, e.g. Haskell, Scala, etc. The actor model: Erlang, but also available for Scala / Java (Akka), C++ (Theron, Casablanca, ...), and other programming languages. My questions: What is the state of the art regarding the development of concurrent applications (e.g. using multi-threading) using the above languages / models? Is this area still being explored or are there well-established practices already? Will it be more complex to program applications with a higher level of concurrency, or is it just a matter of learning new paradigms and practices? How does the performance of highly concurrent software compare to the performance of more traditional software when executed on multiple core processors? For example, has anyone implemented a desktop application using C++ / Theron, or Java / Akka? Was there a boost in performance on a multiple core processor due to higher parallelism?

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• C++ Numerical Recipes &ndash; A New Adventure!

  - by JoshReuben

  I am about to embark on a great journey – over the next 6 weeks I plan to read through C++ Numerical Recipes 3rd edition http://amzn.to/YtdpkS I'll be reading this with an eye to C++ AMP, thinking about implementing the suitable subset (non-recursive, additive, commutative) to run on the GPU. APIs supporting HPC, GPGPU or MapReduce are all useful – providing you have the ability to choose the correct algorithm to leverage on them. I really think this is the most fascinating area of programming – a lot more exciting than LOB CRUD !!! When you think about it , everything is a function – we categorize & we extrapolate. As abstractions get higher & less leaky, sooner or later information systems programming will become a non-programmer task – you will be using WYSIWYG designers to build: GUIs MVVM service mapping & virtualization workflows ORM Entity relations In the data source SharePoint / LightSwitch are not there yet, but every iteration gets closer. For information workers, managed code is a race to the bottom. As MS futures are a bit shaky right now, the provider agnostic nature & higher barriers of entry of both C++ & Numerical Analysis seem like a rational choice to me. Its also fascinating – stepping outside the box. This is not the first time I've delved into numerical analysis. 6 months ago I read Numerical methods with Applications, which can be found for free online: http://nm.mathforcollege.com/ 2 years ago I learned the .NET Extreme Optimization library www.extremeoptimization.com – not bad 2.5 years ago I read Schaums Numerical Analysis book http://amzn.to/V5yuLI - not an easy read, as topics jump back & forth across chapters: 3 years ago I read Practical Numerical Methods with C# http://amzn.to/V5yCL9 (which is a toy learning language for this kind of stuff) I also read through AI a Modern Approach 3rd edition END to END http://amzn.to/V5yQSp - this took me a few years but was the most rewarding experience. I'll post progress updates – see you on the other side !

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• Can Clojure's thread-based agents handle c10k performance?

  - by elliot42

  I'm writing a c10k-style service and am trying to evaluate Clojure's performance. Can Clojure agents handle this scale of concurrency with its thread-based agents? Other high performance systems seem to be moving towards async-IO/events/greenlets, albeit at a seemingly higher complexity cost. Suppose there are 10,000 clients connected, sending messages that should be appended to 1,000 local files--the Clojure service is trying to write to as many files in parallel as it can, while not letting any two separate requests mangle the same single file by writing at the same time. Clojure agents are extremely elegant conceptually--they would allow separate files to be written independently and asynchronously, while serializing (in the database sense) multiple requests to write to the same file. My understanding is that agents work by starting a thread for each operation (assume we are IO-bound and using send-off)--so in this case is it correct that it would start 1,000+ threads? Can current-day systems handle this number of threads efficiently? Most of them should be IO-bound and sleeping most of the time, but I presume there would still be a context-switching penalty that is theoretically higher than async-IO/event-based systems (e.g. Erlang, Go, node.js). If the Clojure solution can handle the performance, it seems like the most elegant thing to code. However if it can't handle the performance then something like Erlang or Go's lightweight processes might be preferable, since they are designed to have tens of thousands of them spawned at once, and are only moderately more complex to implement. Has anyone approached this problem in Clojure or compared to these other platforms? (Thanks for your thoughts!)

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