A control structure for multi-tasking workstations

A control structure based on computer operating system principles is outlined. The structure uses job control blocks, an active queue, critical sections, hierarchical task structure, interprocess communications, and resource allocation to implement an execution engine which segments tasks and provides for control of multiple independent tasks and coordination of multiple actors. The advantages are explained in terms of modular programming, which improves flexibility, online planning, and error recovery. The principles used in this controller are applicable to any workstation controller which performs multiple functions, utilizes online planning, or implements redundant components. These activities will become more important as designers improve workstation utilization rates and reliability