Application Development Support

If you choose to redesign your corporate applications, you'll find that Windows Server 2008 offers a wealth of new features focused on application support. These fall into several categories, such as scalability, availability, manageability, and enhancements to the programming model.

They include:

• Application pooling: With WS08, it is possible to create thread pools for Web applications and apply them to legacy applications that would normally operate in a single process. This gives the application more robustness, since it is no longer tied to a single process.
• Application recycling: Some applications have a tendency to have degraded performance over time due to memory leaks and other programmatic issues. WS08 can recycle a process by gracefully shutting it down and restarting it on a regular basis. This can be done either administratively or through the COM+ software development kit. Administratively, apply it through the Component Services console by right-clicking a COM+ component, selecting Properties, and modifying the elements on the Pooling & Recycling tab.
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  The Component Services console is no longer available by default in WS08 as it was in older versions of Windows Server. To access it, you must either install the Application Server role or create a new console and add the Component Services snap-in. Use Start Menu | Run, type MMC, and in the new console, use File | Add/Remove Snap-in. Scroll down the list until you see Component Services and click Add. Close the snap-in dialog box and save the console.
• Applications as NT services: Now, all COM+ applications can be configured as NT services, making applications load at boot time or on demand as required. Once again, this is performed through the application's properties on the Activation tab.
• Low-memory activation gates: WS08 can check memory allocations before it starts a process, allowing it to shut down an application if it will exhaust memory resources. This allows other applications running on the server to continue operation while only the faulty application fails.
• Web services Any COM+ object can be treated as a Web service and any Web service can be treated as a COM+ object, greatly extending the remoting capabilities of your applications.
• Application partitions In terms of application support, these partitions allow you to host several instances of the same or different versions of COM+ objects on the same server. If, for example, you have 500 customers running a hosted application, you can create 500 partitions, one for each customer, segregating their operational environment from all of the others. Application partitions are created in Active Directory Users and Computers under System | ComPartitions and ComPartitionSets (Advanced Features in the View menu must be enabled). In addition, member servers must have partitions enabled. This is done through Component Services | Computer | Properties | Options tab.
• .NET Framework WS08 includes an integrated version of .NET Framework, version 2.0 by default. In addition, it includes an installable version of .NET Framework version 3.0 and 3.5. Therefore, you can program applications to make use of the Common Language Runtime and integrate them with Extensible Markup Language (XML) Web services to take advantage of this powerful new programming model.
• UDDI services WS08 also includes Universal Description, Discovery, and Integration (UDDI) services, allowing you to publish your Web services either internally or externally. UDDI services are a role that can be added to WS08 servers.
• Simple Object Access Protocol (SOAP) WS08 includes this XML-based protocol to allow full integration with the Web services programming model.
• Message queuing WS08 also includes Microsoft Message Queuing (MSMQ) services. MSMQ provides an asynchronous messaging infrastructure for applications. This allows applications to operate under non-constant networking conditions. MSMQ is integrated with Active Directory Domain Services, where it stores all configuration, security, and status information. MSMQ provides guaranteed network communications even in non-optimal networking conditions. It can be added through the Add Features Wizard.
  Redesigning corporate applications is not a speedy process. It must be planned well before you begin your Windows Server 2008 migration so that applications will be ready to deliver when you perform your infrastructure deployment.

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The major advantage of splitting your environment between resource pools and virtual service offerings is that you can always build a VSO machine running an older version of Windows Server-the Windows Server 2008 Enterprise license supports the use of any older version of Windows as a virtual machine-and use it to run older applications. While this is not the ideal scenario, because you should have all servers migrated to WS08, it does work and it works well to run applications that have not been updated yet.

Legacy Application and Software Testing

Whether or not you convert your applications and upgrade your software, one of the key elements of your WS08 migration will rest with your application testing strategy. Every existing server application and software product in your legacy network must be tested under your new network conditions in order to ensure that it behaves in the proper manner while running under Windows Server 2008. It is also a good idea to repackage legacy application installations to integrate them with the Windows Installer service. All software that boasts the "Designed for Windows" logo is integrated into this service. You should also ensure that all of the corporate applications you redesign for WS08 should be integrated with this service as well.

CAUTION: Even if you have existing applications running under previous versions of Windows Installer, you will need to upgrade them to run with Windows Installer version 4, which has been upgraded to work with the User Account Control features found in Vista and WS08.

This will give all of your applications additional robustness and stability at little cost, since every software product or application must be configured to install automatically anyway. In addition, it will provide you with a single unified installation and deployment method for all software products.

TIP: Altiris, part of Symantec, offers Wise for Windows Installer and Wise Package Studio (www.wise.com) and Macrovision offers AdminStudio (www.installshield.com) to repackage software installations and integrate them with the Windows Installer service as well as to package new applications. Also, remember to test all of your software and application installations in user mode to ensure that they behave properly on WS08 with limited access rights.

Use rigorous testing methods and ensure that expert users are part of your acceptance test group for each application or software product. This will help you guarantee that the software or application provides all the features they expect, since you can't be an expert on every aspect of every program in your network.