NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
APRIL 2019 EXAMINATION

COURSE CODE: CIT752

COURSE TITLE: Operating Systems Concept

CREDIT: 2 Units

TIME ALLOWED: 2 Hours

INSTRUCTION: Answer Question 1 and any other THREE (3) Questions

1a) ) List the issues for co-operating processes (1½  marks)

b) List the components/content of the Thread Control Block (TCB). (1½ marks)

c) State the conditions under which a parent process may terminate the execution of a child process. (3 marks)

d) What is instant messaging? What are its vulnerabilities? (2 marks)

e) List the components of a X.509 Certificate (3 marks)

f) In asynchronous communications, a typical frame for transmitting character data has four components. Enumerate them. (6 marks)

g) Operating system usually comes in two interfaces, describe each interface.             (5 marks)

h) State any six functions of Operating Systems (3 marks)

2a) Enumerate the types of scheduling  (6 marks)

b) Tabulate the specific tasks performed by process scheduler and the mechanism responsible for each task? (6 marks)

c)  State the primary purpose of interrupts in CPU program execution. (3 marks)

3a) Enumerate reasons for providing an environment that allows process co-operation (6 marks)

b) What is a Thread?  (2 marks)

c) State the benefits of Thread over Process. (4 marks)

d) State one advantage and two disadvantages of Relocation. (3 marks)

4a) In a tabular form, state any five differences between the OSI model and the TCP/IP model  (10 marks)

b) Highlight the system objectives which typical process scheduling policies aim to satisfy. (5 marks)

5a) Describe briefly how interrupts work (6 marks)

b) Explain briefly what is meant by Inter Process Communication (3 marks).

c) State the various ways by which IPC can be implemented. (3 marks)

d) Give a summary of the recommendations necessary for effective inter process communication. (3 marks)