Electrical Engineering Department
4th Year Computer and Systems
ECOMP 422: Computer System Programming
Final Exam
2021/2020
Time: 3 Hrs grades: 100
Solve the following questions
Q-1)
a- Describe the different categories of system programs? (10 points)
b- What are the primary data structures used by the Windows OS for threads management? (9 points)
Q-2)
a- Consider the following page reference string,
1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6.
Assume we have four page frames for each process. Determine the number of page faults for FIFO,
LRU and Optimal replacement algorithms. (15 points)
b- What are the benefits of using threads? (8 points)
Q-3)
a- When does the priority inversion problem occur? How can we solve it? (10 points)
b- Assume that we have the following workload, (18 points)
Process P1 P2 P3 P4
CPU Time 53 17 68 24
Arrival time 0 5 10 20
Find the average waiting and turnaround times for FCFS, SJF and RR (quantum = 20) scheduling
algorithms.
Solve only two of the following questions
Q-4)
A- What are the main advantages of the micro-kernel approach to system design? How do user
programs and system services interact in a microkernel architecture? What are the disadvantages of
using the microkernel approach? (10 points)
b- What is the cause of thrashing? How does the system detect thrashing? Once it detects thrashing,
what can the system do to eliminate this problem? (5 points)
1
Q-5)
a- Consider a computer system where the degree of multiprogramming is fixed at four. The system was
recently measured to determine utilization of CPU and the paging disk. The results are one of the
following. For each case, Can the degree of multiprogramming be increased? Why?
i. CPU utilization 13 percent; disk utilization 97 percent (2 points)
ii. CPU utilization 87 percent; disk utilization 3 percent (2 points)
iii. CPU utilization 13 percent; disk utilization 3 percent (2 points)
b- Consider the RPC mechanism. Describe the undesirable circumstances that could arise from not
enforcing either the "at most once" or "exactly once" semantics. Describe possible uses for a
mechanism that had neither of these guarantees. (9 points)
Q-6)
a- Describe how can we use the transactional memory and OpenMP approaches to solve the critical
section problem? What is the advantages of each approach? (9 points)
b- Address binding of instructions and data to memory addresses can happen at three different stages,
what are these stages? (6 points)
