Abstract The problems of idle processor reactivation and the detection of the termination of a parallel activity are investigated. We have proposed a simultaneous access design to handle both problems. The design allows n processors to access it at every constant time cycle, and both problems are solved in O(log n) time. The hardware overhead for the design is O( n). We have also proved the correctness of our design in reactivating idle processors and detecting the termination of a parallel activity.