1. The figure below shows a tunnel going through a mountain and two streets
parallel to each other—one at each end of the tunnel. Traffic lights are located
at each end of the tunnel to control the cross flow of traffic through each inter-
section. Based on this figure, answer the following questions:
a. How can deadlock occur, and under what circumstances?
b. How can deadlock be detected?
c. Give a solution to prevent deadlock and starvation.
2. Consider the directed graph shown below and answer the following questions:
a. Is this system deadlocked?
b. Which, if any, processes are blocked?
c. What is the resulting graph after reduction?
R1 – P1
R2 – P2
R3 – P3
3. For the systems described in Questions 13 through 16 below, given that all
of the devices are of the same type, and using the definitions presented in the
discussion of the Banker’s Algorithm, answer these questions:
a. Calculate the number of available devices.
b. Determine the remaining needs for each job in each system.
c. Determine whether each system is safe or unsafe.
d. If the system is in a safe state, list the sequence of requests and releases
that will make it possible for all processes to run to completion.
e. If the system is in an unsafe state, show how it’s possible for deadlock
to occur.
13. This system has 16 devices.
Job No.Devices Allocated Maximum RequiredRemaining Needs
Job 158
Job 239
Job 348
Job 425
4. Compare the processors’ access to main memory for the loosely coupled
configuration and the symmetric multiprocessing configurations. Give a
true-to-life example where the symmetric configuration might be preferred.
5. Explain the similarities and differences between the critical region and
working set.
