.NET and COM Interoperability Handbook, The

How the Runtime Locates Assemblies

Now that I have discussed the contents of an assembly (metadata and MSIL), I can turn my attention to how the CLR locates assemblies prior to running them. One of the key differences between the .NET Framework and COM is the notion of side-by-side execution. In a nutshell, this is the idea that two completely different versions of a component may be resident and even executing at the same time on a single machine. With COM, each COM class (CLSID) on a machine has entries in the registry under the HKEY_CLASSES_ROOT key that identifies the complete path to the DLL or executable that implements the type. There can only be one path for any given CLSID, so there can only be one implementation of a particular type ...