Question Paper: Operating Systems : Question Paper Jun 2012 - Computer Science Engg. (Semester 5) | Visveswaraya Technological University (VTU)
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Operating Systems - Jun 2012

Computer Science Engg. (Semester 5)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) What is an Opeating System? Bring out the requirements of.
(i) Real time operating systems
(ii) Distributed operating systems.
(10 marks)
1 (b) What are system calls? Explain the different categories of the system calls.(10 marks) 2 (a) Explain the process state with a diagram. What is the need for a context switch?(7 marks) 2 (b) What are the differences between user level threads and kernal supported threads?(5 marks) 2 (c) For the following example calculate average waiting time and average turn around time by using FCFS, preemptive SJF and RR (1 time unit) CPU scheduling algorithms.

Jobs Arrival time Brust time
P1 0 8
P2 1 4
P3 2 9
P4 3 5
(8 marks) 3 (a) What is critical section problem? How does a semaphore solve the critical section problem? Discuss whether semaphore satisfy the three requirements for a solution to the critical section problem.(8 marks) 3 (b) What are monitors? Explain with an example program request.(4 marks) 3 (c) Describe the monitor solution to the classical dining philospher's problem.(8 marks) 4 (a) What is deadlock? Explain the necessary conditions for its occurrence.(6 marks) 4 (b) Explain with an example how resource allocation graph is used to describe the deadlock.(6 marks) 4 (c) System consists of five processes (P0, P1, P2, P3, P4) and three source (R1, R2, R3). Resouce type R1 has 10 instances, resources type R2 has 5 instances and R3 has 7 instances. THe following snapshot of the system has been take:
Jobs Allocation Max Available
R1 R2 R3 R1 R2 R3 R1 R2 R3
P0 0 1 0 7 5 3 3 3 2
P1 2 0 0 3 2 2
P2 3 0 2 9 0 2
P3 2 1 1 2 2 2
P4 0 0 2 4 3 3

Calculate the content of matrix need and find out safe sequence by using Banker's algorithm.
(8 marks)
5 (a) Distinguish between:
(i) Logical address space and physical address space
(ii) Internal fragmentation and external freagmentation
(iii) Paging and segmentation
(6 marks)
5 (b) Explain with the help of supporting hardware diagram how the TLB improves the performance of a demand paging system.(10 marks) 5 (c) Given memory partitions of 100 k, 500 k, 200 k, 300 k and 600 k (in order) how would each of the first fit, best fit and worst fit algorithms work place processes of 212 k, 417 km, 112 k and 426 k (in order)? Which algorithm makes the most effiecient use of memory?(4 marks) 6 (a) Explain the different types of files.(5 marks) 6 (b) Name the different file allocation methods. Explain the linked allocation of file implementation with merits and demetis.(8 marks) 6 (c) Define file system. Explain the different directory structure.(7 marks) 7 (a) What is disk scheduling? Explain any three disk scheduling methods with examples.(10 marks) 7 (b) What is swap space management? Explain.(5 marks) 7 (c) What is access matrix? Explain the access matrix with domains as objects.(5 marks)


Write short notes on the following :-

8 (a) Process management in Linux.(6 marks) 8 (b) Page replacement algorithms.(8 marks) 8 (c) Steps in handling a page fault.(6 marks)

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