JUNE 2000

Question Paper of CS-13 – Operating Systems of June 2000 from IGNOU

Time : 3 Hours
Max. Marks : 75

Note: Question 1 is compulsory.
Answer any three from the rest.

1. (a) Hierarchical directories are more complex to manage than flat files, but their advantages are considered to outweight their drawbacks by many system designers. Explain why.

(b) Design algorithms/functional specifications for the basic range of file-related system services given below :
(i) CREATE
(ii) SEEK
(iii) READ
(iv) WRITE

(c) Discuss the queuing implementation of Semaphores. The algorithm should be nearer to ‘C’ Language implementation

2. (a) Any synchronization problem that can be solved with semaphores can be solved with messages and vice versa. Explain the reasoning you need to come up with in your answer.

3. (a) Devise and discuss the Change and Roberts algorithm for election of a successor in a distributed operating system and explain the performance issues.

(b) State all requirements of a “good” solution to the Mutual Exclusion problem in distributed system 4. (a) Discuss various issues related to hardware support for paging scheme of memory management.

(b) Contrast demand segmentation with demand paging. Explain the trade-offs involved in a page allocation of non-contiguous memory allocation.

5. (a) Compare and contrast different authentication techniques.

(b) Compare an contrast the formal models of protection, the Access-control matrix with Take-Grant model.

(c) Compare and contrast Public-key cryptography technique with Conventional cryptography technique.

6. (a) Devise and discuss the Misra’s algorithm for regeneration of a lost token and explain the performance issues.

(b) Explain the implementation scheme of concurrency control and deadlocks in distributed systems/,

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