From V to Vanguard: The Evolution of a Distributed Object-Oriented Microkernel Interface

The Vanguard operating system kernel was designed and implemented as a research testbed for distributed applications and higher-level operating system services. Using the design of the V-System as a starting point, we developed an extensible set of operating system services, organized in an object type hierarchy. We also implemented a modular OS (micro)kernel that implements these services. An important part of any microkernel design is its exported interface, as the design of this interface affects the ease with which programmers can develop higher-level operating system services on top of the kernel. In this paper we describe several notable features of the Vanguard microkernel interfacein particular, its process and object model, its object identification scheme, and its use of group communication. We show how these features lead to a simple yet powerful interface that avoids the need to provide an excessive number of operations.