Support for 32-bit programs on 64-bit server clusters is included in Windows Server 2003 Service Pack 1 and in x64-based versions of Windows Server 2003

This article describes new functionality that is introduced in Microsoft Windows Server 2003 Service Pack 1 (SP1) and in x64-based versions of Windows Server 2003. Windows Server 2003 with SP1 and x64-based versions of Windows Server 2003 let you run 32-bit programs on a 64-bit Windows Server 2003-based server cluster.

Resource DLLs for 32-bit programs cannot run on a 64-bit computer that is running a 32-bit version of Windows Server 2003 without any service packs installed. Therefore, you cannot run 32-bit programs on a 64-bit server cluster. In this scenario, you must use a 64-bit version of the resource DLL.

Windows Server 2003 with SP1 and x64-based versions of Windows Server 2003 include changes that let 32-bit programs run on a 64-bit server cluster. When a 32-bit program runs, the 32-bit resource monitor runs in parallel with the 64-bit resource monitor.

Note In Windows Clustering, a resource monitor is a component that handles communication between a particular resource and the Cluster service. Resource monitors are created by the Cluster service as resources are brought online. A resource monitor tracks the online or offline state of one or more resources.

In Windows Server 2003 with SP1 and in x64-based versions of Windows Server 2003, you can run a 32-bit cluster-aware program on a 64-bit server cluster subject to the following constraint: A 32-bit cluster administrator extension DLL does not work on a 64-bit operating system. This constraint is because 32-bit cluster administrator extension DLLs are registered to be loaded in process into the native 64-bit Cluster Administrator program in the 64-bit operating system. (Loading a DLL in process is also known as loading "in proc.") This constraint may exist for any one or more of the 32-bit cluster administrator extension DLLs that your program requires. To work around this issue, use one of the following methods:

• Use a 32-bit client computer to manage the cluster-aware program remotely.
• Use a 32-bit Cluster Administrator program to manage the cluster-aware program locally on the 64-bit server cluster from within a complete 32-bit Microsoft Windows on Windows (WOW) environment. In this scenario, the 32-bit Cluster Administrator program successfully loads the 32-bit extension DLL in process.
• Recompile the cluster administrator extension DLL as a 64-bit DLL. After you recompile the DLL, the DLL can be loaded in process into the native 64-bit Cluster Administrator program. The DLL can also be managed by using the native 64-bit Cluster Administrator program.

For additional information about Windows Clustering technologies, visit the following Microsoft Web site:

Technical support for Windows x64 editions

Your hardware manufacturer provides technical support and assistance for Microsoft Windows x64 editions. Your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about Microsoft Windows Server 2003 x64 editions, visit the following Microsoft Web site: