Worker Process Isolation Mode (IIS 6.0)
IIS 6.0 worker process isolation mode takes the concept of application isolation, which was introduced in IIS 4.0, one step further. In IIS 6.0, you can isolate one application from another so that an error in one application does not affect another application running in a different process. This application isolation mode provides better isolation while not incurring a performance penalty for isolation.
Worker process isolation mode loads application code — for example, ASP and ASP.NET applications — into the worker process only. By isolating application code in the worker process, this application isolation mode ensures a reliable environment for an application server: the WWW service, IIS Admin service, and HTTP.sys can run continuously despite any service interruptions that occur in a worker process. Also, Web sites running in the worker processes are not affected by failures in other worker processes because they are isolated from each other through operating system process boundaries.
Worker process isolation mode uses all of the new IIS 6.0 core components and supports application pooling, recycling, and health monitoring features.