UNIVERSITY EXAMINATIONS: 2011/2012
YEAR 1 EXAMINATION FOR THE BACHELOR OF SCIENCE IN
INFORMATION TECHNOLOGY
BIT 1302 OPERATING SYSTEM
DATE: APRIL 2012 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One and Any other Two Questions
QUESTION ONE
a) Briefly explain the following
i) Kernel (2Marks)
ii)Thrashing (2Marks)
iii) Polling (2Marks)
iv) Stream (2Marks)
b) Define interrupts and explain the three sources of interrupts in OS. (6Marks)
c) Discuss five characteristics of modern operating systems. (5Marks)
d) Describe three Replacement policies for paged systems. (6Marks)
e) Describe five factors to consider when selecting a file design method. (5Marks)
QUESTION TWO
a) Identify and explain any two fetch algorithms. (4Marks)
b) Discuss the services provided by the Operating System (7Marks)
c) Briefly explain the functions of O.S Kernel in process management (6Marks)
d) Explain the role the PCB plays during interrupt handling. (3Marks)
QUESTION THREE
a) Give the states that a process can be in. (2Marks)
b) Briefly explain the reasons for process switch. (5Marks)
c) Discuss the principles of I/O software (5Marks)
d) Discuss four measures that can be undertaken to ensure security of the computer system. (8Marks)
QUESTION FOUR
a) Explain the following memory allocation schemes
i. Contiguous allocation (2Marks)
ii. Segmentation (2Marks)
b) List four operations that are associated with files (4Marks)
c) Explain two approaches that can be used to store files in a disk pointing out advantages and
disadvantages of each. (8Marks)
d) Describe the information, which would be stored in a typical directory system pertaining to the file
within the directory. (4Marks)
QUESTION FIVE
a) Explain four difficulties with Concurrency. (4Marks)
b) Discuss the conditions for Deadlock (8Marks)
c) Describe four strategies to overcome deadlock ones it is Detected. (8Marks)
