Programming Visual Basic .NET

Application Domains

Application domains are to the CLR what processes are to an operating system. It may be surprising to note that the CLR can run multiple .NET applications within a single process, without any contention or security difficulties. Because the CLR has complete control over loading and executing programs, and because of the presence of type information, the CLR guarantees that .NET applications cannot read or write each other’s memory, even when running in the same process. Because there is less performance overhead in switching between application domains than in switching between processes, this provides a performance gain. This is especially beneficial to web applications running in Internet Information Services (IIS), where scalability is an issue.