operating system feb 28

CS 410 Operating Systems Homework 04

All the questions are worth 3 pts/ea and the problems 5 pts/ea unless noted otherwise.

Review Questions Chapter 5 5.1 List four design issues for which the concept of concurrency is relevant. 5.3 What is the basic requirement for the execution of concurrent processes? 5.4 List three degrees of awareness between processes and briefly define each. 5.5 What is the distinction between competing processes and cooperating processes? 5.6 List the three control problems associated with competing processes and briefly define each. 5.7 List the requirements for mutual exclusion. 5.11 What is a monitor? 5.12 What is the distinction between blocking and nonblocking with respect to messages?

Chapter 6 6.2 What are the three conditions that must be present for a deadlock to be possible? 6.3 What are the four conditions that create deadlock? 6.4 How can the hold-and-wait condition be prevented? 6.5 List two ways in which the no-preemption condition can be prevented. 6.6 How can the circular-wait condition be prevented?

Problems Chapter 5 5.2. Consider Dekker’s algorithm written for an arbitrary number of processes by changing the statement executed when leaving the critical section from

turn = 1 – i/* i.e. P0 sets turn to 1 and P1 sets turn to 0 */ to turn = (turn + 1) % n /* n = number of processes */

Evaluate the algorithm when the number of concurrently executing processes is greater than two.

5.3. Demonstrate that the following software approaches to mutual exclusion do not depend on elementary mutual exclusion at the memory access level: a. The bakery algorithm. b. Peterson’s algorithm.

5.4. At the beginning of Section 5.2, it is stated that multiprogramming and multiprocessing present the same problems, with respect to concurrency. This is true as far as it goes. However, cite two differences in terms of concurrency between multiprogramming and multiprocessing.

5.8. Is busy waiting always less efficient (in terms of using processor time) than a blocking wait? Explain.

Chapter 6 6.3. For Figure 6.3, provide a narrative description of each of the six depicted paths, similar to the description of the paths of Figure 6.2 provided in Section 6.1.

6.4. It was stated that deadlock cannot occur for the situation reflected in Figure 6.3. Justify that statement.

6.5. a. b. c. d. ⇐ (6 pts total)

6.7.

6.15.

6.16. a. b.

6.17.

6.22.

SUBMISSION Submit a DOCX or PDF document (PDF preferred) through Western Online with the answers to the questions or problems typing the corresponding numbers and questions (or at least the numbers) in bold and in the proper order before your answers (answers not in bold). Use a different font color for all the numbers and questions, than the color used for your answers. You can, as an example, use a blue color for all the numbers and questions, and black font for all your answers. The idea is to make the grading process easy to follow and faster. Points will be deducted if you do not follow these guidelines.

Use the following format to name your document file:

CS410_HW_04_YourLastName-YourFirstName_.pdf (or docx extension)

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