An experimental multi-processor architecture for small business applications

Automated data processing is an essential part of the operation of most medium and large businesses. Unfortunately, system cost and operating complexity have effectively denied the potential benefits to most small enterprises. Outlined in this paper is the design of an experimental multi-processor system intended for such small business applications. Its architecture is highly modular, both in hardware and software, permitting the capabilities of the system to expand as the data processing demands of the system increase. The system uses a master/slave arrangement of microprocessors to realize this expanding capability. In the simplest configuration, the CPU comprises a master and a single slave microprocessor. As the demand on the computer increases, additional slaves can be added until, in the limit, the master functions primarily as the system scheduler. The organization and control of both the hardware and software is presented. The methods used for bus sharing, microprocessor interlacing, and timing are discussed, as well as the techniques used to achieve high speed interrupt response needed to control point of sale terminals, perpetual inventory, and other real time operations. The structure of the system executive, and the mechanism used to allocate system resources and control the execution and interaction of parallel system tasks is described in detail.