One of the toughest deployment issues developers and IT professionals face involves dynamic-link libraries (DLLs). It starts when multiple applications attempt to share a common component like a DLL or a Component Object Model (COM) class. When a new application is installed, the components for the new application may overwrite components of an existing application, causing the existing application to function incorrectly or stop functioning completely.

Solve the problem of overwriting

Typically, one application will install a new version of the shared component that is not backward-compatible with the version already on the computer. Although the newly introduced application will work fine, existing applications that depended on a previous version of the shared component may no longer work.

Side-by-side deployment

Through the use of side-by-side deployment, the .NET Framework solves the problem of overwriting. Side-by-side deployment allows multiple versions of an assembly to be installed and to run simultaneously on the same computer. Authors aren't restricted to maintaining backward compatibility because different applications can use different versions of a shared component. Each application can request to use a specific version of that assembly. Version information is recorded through the common language runtime between pieces of an application. At run time, the common language runtime refers to the recorded information to ensure the proper version of a dependency is loaded.

Isolate application assemblies

By isolating application assemblies, applications always load the components with which they were built and tested. An assembly can be accessed by only one application; it is not shared by multiple applications on the same computer. Therefore, it cannot be affected by changes made to the system by other applications.

.NET-enabled applications are self-contained and can be installed easily using XCOPY. This makes it possible to install desktop applications on client computers using a remote Web server. Actual deployment involves packaging developer code and distributing the packages to the clients and servers on which the application will run.

The .NET Framework eliminates any dependency on the registry, which makes installation, removal, and replication much easier. You can deploy many applications by just copying file sets to disk and running them. To remove or replicate the applications, you can simply delete the files or copy over them.