Bealkowski, Richard.

Providing multiprocessor capability to the class of computers commonly referred to as personal workstations is the next evolutionary step in their development. Uniprocessor workstations limit the user in throughput, reliability, functionality, and architecture. Multiprocessor workstations have the potential of increasing system throughput. A multiprocessor system with expanded architecture derived from a set of heterogeneous processors gives the user a diverse application base within a single system. The replication and diversity offered in systems of this design, when coupled with fault-tolerant design techniques, enhances system reliability. A heterogeneous multiprocessor architecture is presented which combines loosely- and tightly-coupled configurations (multicomputer and multiprocessor). This architecture provides for incremental growth of the system, either by static or dynamic reconfiguration. The software view of the system is that of an object-oriented environment. The object-oriented approach is used to unify the heterogeneous nature of the system. The process is the unit of concurrency in the system and cooperating concurrent processes are supported. A set of system primitives are provided to support the requirements of a heterogeneous multiprocessing environment. A virtual machine layer controls the distribution of processes and allocation of resources in the system. A virtual network is used to provide communication paths and resource sharing. The virtual network is designed to be bridged to an external physical network. The system requirements for a secure and reliable operating environment are incorporated into the design. This system utilizes "hardware porting" as a means to overcome the lag of software support for hardware advances. Rather than software port an entire application base to a new system architecture, hardware porting brings the required instruction set architecture to the applications. This heterogeneous multiprocessor architecture builds on a popular system architecture, the scIBM PS/2 with the Micro Channel system bus. Incorporating a second bus, the scSCSI bus, as a system extension is explored.