MSXML 4.0 and Windows XP

Important This topic explains features that are only relevant when you deploy applications that use MSXML 4.0 to computers running Microsoft® Windows® XP. If you are deploying to computers that use other versions of Microsoft® Windows, such as Windows 2000, Windows NT, Windows Me, or Windows 98, disregard the following information.

Windows XP enables applications to safely share assemblies. When MSXML 4.0 is installed on Microsoft® Windows® XP, it is installed as a shared side-by-side assembly.

Shared side-by-side assemblies are installed into the managed assembly store of the system by Windows Installer. Side-by-side assemblies are authored so that multiple versions can run at the same time without impacting each other. These assemblies are not registered globally on the system, but they are globally available to applications that depend on them.

Note Windows XP Side-by-Side installation should not be confused with the side-by-side installation provided in previous versions of MSXML. The previous side-by-side installation was implemented by modifying GUIDs and ProgIDs. This topic covers Windows XP Side-by-Side installation exclusively.

For Windows XP, you specify dependencies with manifests, which are used as either assembly manifests or application manifests.

Assembly manifest: An XML file that describes a side-by-side assembly. It describes the names and versions of side-by-side assemblies, files, and assembly resources. It also describes the dependence of the assembly on other side-by-side assemblies. It contains binding and activation information that traditionally has been stored in the registry, such as information about COM components, interface stubs, and type libraries. For side-by-side assemblies to be installed, activated, and executed correctly, the assembly manifest must always accompany an assembly on the system.
Application manifest: An XML file that describes the names and versions of shared side-by-side assemblies that the application depends upon and should bind to at runtime. Application manifests are copied into the same folder as the application executable file, or are installed as a resource in the executable file that starts the application.

The following topics provide more information about manifests, MSXML 4.0, and Windows XP.