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Unformatted text preview: 1.Describe briefly four conditions for Deadlock. Mutual exclusion condition o Each resource assigned to 1 process or is available Hold and wait condition o Process holding resources can request additional No preemption condition o Previously granted resources cannot forcibly taken away Circular wait condition o Must be a circular chain of 2 or more processes o Each is waiting for resource held by next member of the chain 2.What are Safe and Unsafe States? At any instant of time, current state of system consisting of E (Resources in Existence), A (Resource Available), C (Current allocation matrix), R (Request matrix) If a system is in safe state no deadlocks. If a system is in unsafe state possibility of deadlock. Avoidance ensure that a system will never enter an unsafe state. 3.Describe briefly the Banker's Algorithm for Multiple Resources. The algorithm for checking to see if a state is safe can be stated. 1. Look for a row, R, whose unmet resource needs are all smaller than or equal to A. If no such row exists, the system will eventually deadlock since no process can run to completion. 2. Assume the process of the row chosen requests all the resources it needs and finishes. Assume the process of the row chosen requests all the resources it needs and finishes....
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This note was uploaded on 12/07/2011 for the course JAPANESE JP3248 taught by Professor Kuoda during the Spring '11 term at Université Stendhal Grenoble 3.
- Spring '11