hw5 - happen if, instead of starting with dirty forks in...

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CSE4/586 (Spring 2009): Homework 5 Due by Apr 23 Thursday, in class. 1. (20 points) In Lamport’s logical clock based mutual exclusion protocol (Chapter 7) why do we need to have the following check for a process i entering the critical section? For all other j , knownT [ j ] must be larger than the timestamp of req i . 2. (20 points) Show that in Lamport’s mutual exclusion protocol, if a process i is executing the critical section, then i ’s request need not be at the top of the request queue ( reqQ ) at another process j . Is this still true when there are no messages in transit? 3. (30 points) In the dining philosopher’s protocol, what kind of undesirable scenario may
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Unformatted text preview: happen if, instead of starting with dirty forks in the initial state, all processes were to start with clean forks? 4. (30 points) Answer the following questions for the hygenic dining philosopher’s protocol in Chapter 8: 1. In the worst case, how much of the neighborhood processes are affected (i.e., starve), when an eating node fails by crushing? (Hint: think about whether it is possible to construct long dependency chains using the priority concept.) 2. In the worst case, how much of the neighborhood processes are affected (i.e., starve), when a thinking node fails by crushing? 1...
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This note was uploaded on 01/04/2010 for the course CSE 123 taught by Professor Qwerty during the Spring '09 term at École Normale Supérieure.

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