Patent US 4,130,865

Computer apparatus which employs a plurality of processing units, a memory unit, and a communication unit, each of the units including a data transfer bus. A bus coupler is provided between each pair of units of differing type to form a distributed data communications network. An addressable, passive task register is associated with one of the units for communication through the couplers and is adapted to register a task priority value associated with a task request, the register being readable by any one of the processor units to obtain the highest priority value registry.