Refer to exams and tests for deadlock understanding.

1. Understanding Deadlock in
Operating Systems
• Causes, Conditions, and Solutions
• Presented by: [Your Name]

2. Introduction to Deadlock
• Deadlock is a situation where a set of
processes are blocked because each process is
holding a resource and waiting for another
resource acquired by another process.
• - Common in multitasking and multiprocessing
environments.

3. Necessary Conditions for Deadlock
• 1. Mutual Exclusion: At least one resource
must be held in a non-shareable mode.
• 2. Hold and Wait: A process is holding at least
one resource and waiting to acquire additional
resources.
• 3. No Preemption: Resources cannot be
forcibly taken from processes holding them.
• 4. Circular Wait: A set of processes are waiting
for each other in a circular chain.

4. Deadlock Example
• - Process P1 holds Resource R1 and waits for
R2.
• - Process P2 holds Resource R2 and waits for
R1.
• - Neither can proceed = Deadlock

5. Deadlock Detection
• - System checks periodically for circular waits
in the Resource Allocation Graph.
• - Algorithms used:
• - Wait-for Graph (WFG)
• - Banker's Algorithm (for safe state check)

6. Deadlock Prevention
• Eliminate one of the necessary conditions:
• - Deny Mutual Exclusion (rarely possible)
• - Deny Hold and Wait
• - Allow Preemption
• - Prevent Circular Wait (resource ordering)

7. Deadlock Avoidance
• - Ensure system never enters an unsafe state.
• - Banker's Algorithm:
• - Checks system’s resource allocation state
before granting a request.

8. Deadlock Recovery
• - Process Termination: Abort one or more
processes to break the cycle.
• - Resource Preemption: Take resources from
some processes and allocate to others.

9. Real-World Examples
• - Database systems
• - Traffic deadlock at intersections
• - Multi-threaded applications

10. Summary
• - Deadlock is a critical issue in OS requiring
careful handling.
• - Prevention, Avoidance, Detection, and
Recovery are key strategies.
• - Understanding resource management helps
minimize deadlocks.

11. Questions & Discussion
• - Any Questions?
• - Thank You!