JUNE 2001

Question Paper of CS-13 – Operating Systems of June 2001 from IGNOU

1. (i) Write an algorithm for bounded buffer producer/consumer problem using monitor. Also describe the problem and algorithm in detail.

(ii) Discuss in detail the distribution of control and the degree o functional specification of the individual processing elements in the three major classes of multiprocessor operating system.

(iii) A processor references five page A ,B,C,D and E in the following order :

A, B,C,D,A,E,B,C,E,D

Assume that the replacement algorithm is LRU and FIFO and out the number of page transfers during the sequence of reference starting with and empty main memory with 3 formes.

2. Discuss various machine level implementation of mutual exculsions in general and of semaphores in particular. Also discuss suitability and efficiency of these algorithms.

3. (a) Summarize the caharacteristics of all forms memory management along the following lines :
H/W requirement and its functionality
Effective memory access time
Wastes memory

(b) Differentiate between the lattice model and the remaining formal models of protection.

4. (a) Explain the routing scheme in multistage switch based system.

(b) Discuss the assumption, properties and differences among the four major models of distributed computing.

5. (a) Discuss the importance of ordering of events in distributed systems. Is ordering of evens important in centralized systems as well ? Why or why not?

(b) Describe the bully�s algorithm for the election of a successor. Also discuss the performance of the algorithm.

6. (a) What are the necessary conditions for deadlock in the centralized environment. Explain through example. Do we have some conditions for deadlock in distributed systems.

(b) Describe two concurrency control protocols through example that can avoid deadlock and are used in distributed systems?

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