This paper describes three basic specializations of design patterns that can be used in implementing the runtime systems of parallel applications. These specializations were discovered while re-designing and re-implementing the runtime system for the Enterprise parallel programming system. Enterprise allows programmers to create, compile, execute, and debug programs that execute over a network of workstations. A previous paper in this conference described its object-oriented user interface. The run-time system is responsible for the execution of user programs. It was recently re-designed using objects to rectify problems with the previous version and to provide an extensible base for further research. This papers details the key object-oriented components of the new system. Although these components were developed in the context of the Enterprise system, they are generally applicable to object-oriented run-time systems for general parallel applications.