UNIVERSITY EXAMINATIONS: 2018/2019
EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE
IN INFORMATION TECHNOLOGY / BACHELOR OF BUSINESS
INFORMATION TECHNOLOGY/ BACHELOR OF SCIENCE IN
APPLIED COMPUTING
BBIT111 BIT1106A BAC OPERATING SYSTEM
FULL TIME/PART TIME/DISTANCE LEARNING
DATE: APRIL, 2019 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One & ANY OTHER TWO questions.
QUESTION ONE
a) Explain the following terms as used in operating systems:
i) Spooling [2Marks]
ii) Thrashing [2Marks]
b) Describe threads and the different types of threads, giving their advantages and
disadvantages of each. [8Marks]
c) With the aid of a diagram, explain the relationship between operating system, computer
hardware, utility programs and application programs [6Marks]
d) With aid of diagrams, describe at least two operating system structures. [4Marks]
e) (i) Briefly explain four main performance criteria used to select a scheduling
algorithm. [4Marks]
(ii) Describe the four conditions for deadlock in Operating System. [4Marks]
QUESTION TWO
a) The process control block is a data structure containing certain important information about
the process. Identify the information contained in the PCB. [6Marks]
b) Briefly explain six factors that may lead to a process switch. [6Marks]
c) Discuss at least four objectives of file management. [8Marks]
QUESTION THREE
a) Security goals of any computer system are decided by its security policies. Briefly explain
three computer security goals that can be set in an operating system. [6Marks]
b) State four types of security threats to consider when designing and implementing any
operating system. [4Marks]
c) Most Modern Operating Systems support memory management with paging. Briefly explain
the following.
i) Page replacement algorithms [4Marks]
ii) Fetch policies, outlining the two classes [3Marks]
iii) Placement algorithm for non-paged system. [3Marks]
QUESTION FOUR
a) Distinguish between a file system and a file control block. [4Marks]
b) List four operations that are associated with files [4Marks]
c) Discuss in detail four file organization methods. [8Marks]
d) Describe two techniques that can be used to manage disk free space [4Marks]
QUESTION FIVE
a) Distinguish between the following pairs of terms:
i) Starvation and Deadlock [2Marks]
ii) Fault avoidance and Error detection [2Marks]
iii) Device driver and Device controller [2Marks]
iv) Paging and segmentation [2Marks]
b) Explain five desirable features of a process scheduling algorithm [5Marks]
c) Describe the operation of Round Robin and Multilevel Feedback Queues scheduling
algorithms. [5Marks]
a) Outline any two factors to consider in operating system design [2Marks]
