 1.1 In a multiprogramming and time-sharing environment, several users share the
system simultaneously. This situation can result in various security problems.
a. What are two such problems?
b. Can we ensure the same degree of security in a time-shared machine as in
a dedicated machine? Explain your answer.
 1.2 The issue of resource utilization shows up in different forms in different types
of operating systems. List what resources must be managed carefully in the
following settings:
a. Mainframe or minicomputer systems
b. Workstations connected to servers
c. Handheld computers
 1.6 How do clustered systems differ from multiprocessor systems? What is
required for two machines belonging to a cluster to cooperate to provide a highly
available service?
 1.10 What is the purpose of interrupts? What are the differences between a trap
and an interrupt? Can traps be generated intentionally by a user program? If so,
for what purpose?
 1.12 Some computer systems do not provide a privileged mode of operation in
hardware. Is it possible to construct a secure operating system for these computer
systems? Give arguments both that it is and that it is not possible.
 2.2 List five services provided by an operating system that are designed to make
it more convenient for users to use the computer system. In what cases it would
be impossible for user-level programs to provide these services? Explain.
 2.3 Describe three general methods for passing parameters to the operating
system.
 2.12 What is the main advantage of the microkernel 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?
 3.2 Describe the actions taken by a kernel to context-switch between processes.
 MS-DOS provided no means of concurrent processing. Discuss three major
complications that concurrent processing adds to an operating system.
 5.1 Why is it important for the scheduler to distinguish I/O-bound programs from
CPU-bound programs?
 5.4 Consider the following set of processes, with the length of the CPU burst
given in milliseconds:
Process
P1
P2
P3
P4
P5
Burst Time
10
1
2
1
5
Priority
3
1
3
4
2
The processes are assumed to have arrived in the order P1, P2, P3, P4, P5, all at
time 0.
a. Draw four Gantt charts that illustrate the execution of these processes using
the following scheduling algorithms: FCFS, SJF, nonpreemptive priority (a
smaller priority number implies a higher priority), and RR (quantum =1).
b. What is the turnaround time of each process for each of the scheduling
algorithms in part a?
c. What is the waiting time of each process for each of the scheduling
algorithms in part a?
d. Which of the algorithms in part a results in the minimum average waiting
time (over all processes)?
 5.5 Which of the following scheduling algorithms could result in starvation?
 5.7 Consider a system running ten I/O-bound tasks and one CPU-bound task.
Assume that the I/O-bound tasks issue an I/O operation once for every
millisecond of CPU computing and that each I/O operation takes 10 milliseconds
to complete. Also assume that the context-switching overhead is 0.1 millisecond
and that all processes are long-running tasks. What is the CPU utilization for a
round-robin scheduler when:
a. The time quantum is 1 millisecond
b. The time quantum is 10 milliseconds
 5.10 Explain the differences in the degree to which the following scheduling
algorithms discriminate in favor of short processes:
a. FCFS
b. RR
c. Multilevel feedback queues
Deadline: October 17, 2005
Email your answers to the TA at: tompson2001@hotmail.com
Important – make sure you get an acknowledgement