Changes to the Windows NT OS base

One key goal of the project was to make the cluster service a separate, isolated set of components. This reduces the possibility of introducing problems into the existing code base and avoids complex schedule dependencies. We did however, need to make changes in a few areas to enable the cluster features. The ability to dynamically create and delete network names and addresses was added to the networking code. The file system was modified to add a dismount capability, closing open files. The I/O subsystem needed to deal with disks and volume sets being shared between multiple nodes. Apart from these, and a few other minor modifications, cluster capabilities were built on top of the existing operating system features.