| Operating within the bounds of a single address space has, in general, always been the simplest model for computing. The demands of modern computing have introduced various complexities to overcome the limitations of available hardware and to extend communications between computers. These complexities include the use of virtual address spaces to alleviate address space limitations of the hardware, and to provide protection between computational entities on the same machine. Multiple virtual address spaces and interprocess communication have become the standard paradigm on which complex operating systems are built. This research explores an alternative to the standard paradigm: reverting to the single address space model including distributing it across the network. The outcome of this research, which is supported by several theses and culminates with this dissertation, indicates that a single address space paradigm can reduce the complexity of system and application software and may greatly reduce the cost to design, maintain, and execute distributed computer programs.; This dissertation in particular documents to date the effort to implement the Sombrero Single Address Space Distributed Operating System. A kernelless modular system design and a new protection mechanism that offers zero-cost domain switches have been successfully implemented.; Sombrero's single address space design is ideal for multiprocessor environments, real-time and embedded environments, distributed shared memory, and load balancing. It lays the foundation for future “hands on” research for distribution and fault tolerance in a single address space. |
