A simple a microprocessor-based control system has three interrupting devices
A, B, and C. The micr oprocessor checks for interrupts frequently, once every
10 milliseconds (msec). The device A has priority over the other two devices,
and B has priority over C. This m eans that if all the devices are interrupting,
only A is serviced. If only B and C are interrupting, only B will be served.
If only C is interrupting, it will be served. The devices A, B, and C generate interrupts statistically independently with probabilities of 0.1, 0.4, and 0.6,
respectively. Their respective interrupt service times are 5, 3, and 2 msecs.
Unserviced interrupts are lost. There is no queuing at all.
Determine each of the probabilities with which the microprocessor services
A, B, or C after it checks. Also determine the average time spent on interrupt
service during a 10 msec time period.