an analytic model of the hasp execution task monitor
The HASP Execution Task Monitor periodically rearranges the OS/360 dispatching chain to give tasks pre-emptive execution priority in inverse order to their CPU utilization history. The effect is to keep the I/O bound tasks active and to prevent CPU bound tasks which have high priority due to the partition/initiator priority heirarchy of OS from locking out other tasks. This paper develops a simple model of the Execution Task Monitor and employs it to study the effectiveness of the monitor in improving system performance. A modified strategy for monitor control is postulated and investigated for the case of task execution in memory of varying speed. This work was supported by National Science Foundation Grant DJ-33764X
modeling hasp os/360 dispatching scheduling performance evaluation