Dead Lock in operating system
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Deadlock occurs when two or more processes are waiting for resources held by each other in a circular chain, resulting in none of the processes making progress. There are four conditions required for deadlock: mutual exclusion, hold and wait, no preemption, and circular wait. Deadlock can be addressed through prevention, avoidance, detection, or recovery methods. Prevention aims to eliminate one of the four conditions, while avoidance techniques like the safe state model and Banker's Algorithm guarantee a safe allocation order to avoid circular waits.
Dead Lock in operating system
- 2. What is Deadlock? • A dead-lock is a situation in which two devices or computer programs sharing the same resource are affectively stopping each other from accessing the resource. • Final result in both programs closing to function.
- 3. Four conditions for Deadlocks? 1. Mutual Exclusion condition 2. Hold & wait condition 3. No preemption condition 4. Circular wait condition
- 6. How to Handle deadlocks? • Four major areas of interest in deadlock research 1) Deadlock prevention 2) Deadlock Avoidance 3) Deadlock detection 4) Deadlock Recovery
- 7. Deadlock prevention? • Prevention eliminates one of four conditions 1. Elimination of Mutual Exclusion 2. Elimination of Hold & wait condition 3. Elimination of No preemption condition 4. Elimination Of Circular Wait Condition
- 8. How deadlock can be avoided? • We can avoid the situation of deadlocked by: 1. Safe state 2. Banker’s Algorithm 3. Resource Allocation Graph
- 9. Safe state • State is safe because OS can definitely avoid deadlock by blocking any new requests until safe order is executed. This avoids circular wait condition. Process waits until safe state is guaranteed.
- 11. Resource Allocation Graph • If we have a resource allocation system with only one instance of each process, a variant of the resource allocation graph can be used for deadlock avoidance.
- 12. Deadlock Detection? • Determines if deadlock has occurred. • Identifies those processes & resources involved in the deadlock.
- 13. Any Question!
- 14. Thanks