US Patent 7257815 Methods and system of managing concurrent access to multiple resources

The present invention is directed to a method and system for managing concurrent access to multiple resources. Resources are assigned to sets in such a way that it is safe to concurrently access any combination of resources in a resource set. For each resource set, a virtual machine is defined and associated with the resource set. An application is assigned to a virtual machine. When an application requests access to a resource not in the application's virtual machine, access control lists are consulted to determine whether the access should be allowed, given the other resources already accessed by the application.