It is topic on the deadlocks which is used in os

1. Deadlocks in Operating Systems
A Complete Overview

2. What is a Deadlock?
• • A deadlock is a situation where a set of
processes are blocked.
• • Each process is waiting for a resource held
by another process.
• • No process can proceed.

3. Necessary Conditions (Coffman
Conditions)
• The following four conditions must hold
simultaneously:
• • Mutual Exclusion
• • Hold and Wait
• • No Preemption
• • Circular Wait

4. Resource Allocation Graph
• • Used to represent resources and processes.
• • A cycle in the graph indicates a possible
deadlock.
• • For one resource per type, cycle = deadlock.

5. Methods for Handling Deadlocks
• • Deadlock Prevention
• • Deadlock Avoidance
• • Deadlock Detection
• • Deadlock Recovery

6. Deadlock Prevention
• • Ensures at least one Coffman condition does
not occur.
• • Break one of the conditions:
• - Mutual Exclusion
• - Hold and Wait
• - No Preemption
• - Circular Wait

7. Deadlock Avoidance (Banker's
Algorithm)
• • Works by checking safety state.
• • Ensures system stays in safe state.
• • Allocate resources only if safe.

8. Deadlock Detection & Recovery
• • Detection algorithms identify cycles.
• • Recovery methods:
• - Process termination
• - Resource preemption

9. Real-Life Examples
• • Two trains waiting on a single-track section.
• • Two people trying to pass in a narrow
hallway.
• • Printers and scanners shared in network.