Ics2212:Operating Systems 1 Question Paper
Ics2212:Operating Systems 1
Course:Bachelor Of Information Technology
Institution: Meru University Of Science And Technology question papers
Exam Year:2014
a. Memory management is one of the most important services provided by the operating system. List the four responsibilities an operating system has in managing memory. (2 Marks) b. Describe any three methods used when accessing files in the computer system. (3 Marks) c. Draw and discuss the various process transformation states, properly articulating the various transitions. (4 Marks) d. Identify and explain the four conditions needed to hold to have a good solution for the critical section problem(mutual exclusion) (4 Marks) e. CPU scheduling goals are contradictory but achievable. State the four job scheduling goals, substantiate this statement. (2 Marks) f. Write short notes on the following terms: (6 Marks) i. Context switch ii. Parallel processing iii. Pre-emptible resources g. When memory is allocated dynamically, the operating system must manage it. The two ways to keep track of memory usage is bit maps and linked lists. Briefly explain the two ways. (6 Marks) h. When a page fault occurs, the operating system has to choose which page to remove from the memory to make room for the page that has to be brought in. Outline any three page replacement algorithms. (3 Marks)
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QUESTION TWO – 20 MARKS
a. Consider the following set of processes whose arrival times on the ready queues and the lengths of their CPU bursts are given in milliseconds. Jobs Arrival Time CPU Burst (in seconds)
J1 0 6 J2 2 3 J3 4 12 J3 6 8 i. Using the Quantum of four milliseconds, draw a chart for RR scheduling algorithms. (3 Marks) ii. Calculate the turnaround time and the average turnaround time for the a(i) above. (3 Marks) iii. Explain priority scheduling, using the data provided above substantive your answer. (3 Marks) b. System administrator of MUCST has approached you for some advice on what could be the causes of computer slowness when executing his departmental operations. He has advanced a theory of deadlocks. Advise him on the best strategies he could put in place to help in detecting and recovering from the deadlocks. (6 Marks) c. Distinguish between the interrupts and page faults. (2 Marks) d. During IPC there is a possibility of race condition occurring when processes compete to enter the critical section. Explain the term critical section. (3 Marks)
QUESTION THREE – 20 MARKS
a. Distinguish between the fixed memory partitions and the variable memory partitions, giving advantages of the variable partitions over the fixed partitions. (3 Marks) b. Computer servers handle huge number of processes that require proper implementation strategies. Explain a tool used by the operating system designers for the implementation of the processes, properly articulating its components. (6 Marks) c. Mr Mwatela manufactures computer processors, he has approached you to explain the operation of the scheduler and also describe the four CPU scheduling algorithms to him. (8 Marks) d. Briefly outline the relevance of the memory compaction in memory management. (3 Marks)
QUESTION FOUR – 20 MARKS
a. Discuss the evolvement of the operating systems, showing how the development has improved the functioning of the information systems over time. (6 Marks) b. Mr Murungi is an operating systems manufacturer; he wants to design a memory management system using multiprogramming with fixed partitions mechanisms using either a single queue or multiple queues. Discuss the two methods and advice Mr Murungi on the best mechanism to use and why? (5 Marks) c. Mr Mwala a data entry clerk at the Ministry of Education works with files and directories to carry out his operations as a clerk. Outline Mr Mwala’s five operations that he carries out on files. (5 Marks) d. Deadlocks do not just occur, outline the four conditions that lead to deadlocks. (4 Marks)
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QUESTION FIVE – 20 MARKS
a. i. Differentiate between off-line and on-line spooling. (2 Marks) ii. Describe the importance of buffering in the I/O subsystems of operating system. (4 Marks) b. Operating systems are structured differently depending on the mode of operation and functions they are intended to perform. Briefly explain the four operating systems structures showing their distinct interfaces and mode of operation. (6 Marks) c. Operating system designers must employ the best strategies of ensuring mutual exclusion so as to eradicate the race conditions as processes compete for resources in the computer. Briefly discuss the four approaches of achieving mutual exclusion by busy waiting. (8 Marks)
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