The early 1980s saw the development of some rather sophisticated distributed systems. These were not merely networked file systems: rather, using remote procedure calls, hierarchical naming, and what would now be called middleware, they allowed a collection of systems to operate as a coherent whole. One such system in particular was developed at Newcastle that allowed pre-existing applications and (Unix) systems to be used, completely unchanged, as components of an apparently standard large (multiprocessor) Unix system. The Distributed Secure System (DSS) described in our 1983 paper proposed a new way to construct secure systems by exploiting the design freedom created by this form of distributed computing. The DSS separated the security concerns of policy enforcement from those due to resource sharing and used a variety of mechanisms (dedicated components, cryptography, periods processing, separation kernels) to manage resource sharing in ways that were simpler than before. In this r...
Brian Randell, John M. Rushby