Obviously, there can be more than one PD to be ”alive”, which means many programs can be executed concurrently. A PD can drive its program to run independently. Also, a PD may cooperate with other PD or PDs via some synchronized mechanism.
Obviously, there can be more than one PD to be ”alive”,which means many programs can be executed concurrently.A PD can drive its program to run independently. Also, aPD may cooperate with other PD or PDs via some synchronizedmechanism.