Fault-tolerant real-time task scheduling in the MAFT distributed system

The development of the task scheduling mechanism for the multicomputer architecture for fault-tolerance (MAFT) is discussed. MAFT is a distributed computer system designed to provide high performance and extreme reliability in real-time control applications. The impact of the system´s functional requirements, fault-tolerance requirements, and architecture on the development of the scheduling mechanism is examined. MAFT uses a priority-list scheduling algorithm modified to provide extreme reliability in the monitoring of tasks and the detection of scheduling errors. It considers such issues as modular redundancy, Byzantine agreement, and the use of multiversion software and dissimilar hardware. An example of scheduler performance with a realistic workload is presented