Deadlock Detection - Animation

Resource Allocation Graph Ready for Detection

Allocation Matrix

Process	R1	R2	R3
P1	0	1	0
P2	2	0	0
P3	3	0	2
P4	2	1	1

Request Matrix

Process	R1	R3
P1	2	2
P2	1	1
P3	0	1
P4	0	2

Detection Results --

No Deadlock Detected - System is in Safe State

Select an algorithm and click Detect to begin deadlock detection

About Deadlock

A deadlock occurs when processes are blocked forever, waiting for resources held by each other.

Mutual Exclusion: Resources cannot be shared
Hold and Wait: Process holds resources while waiting
No xH4: Resources cannot be forcibly taken
Circular Wait: Circular chain of waiting processes

Detection Algorithms

Resource Allocation Graph:

1. Create RAG with processes and resources 2. Draw allocation and request edges 3. Check for cycles in the graph 4. If cycle exists → Deadlock detected

Banker's Algorithm:

1. Check if system is in safe state 2. Find process that can complete 3. Release its resources 4. Repeat until all processes complete 5. If stuck → Deadlock detected

Detection Methods

Resource Allocation Graph:

Visual representation of resource allocation
Cycle detection indicates deadlock
Works for single instance resources

Wait-For Graph:

Simplified version of RAG
Shows only process dependencies
Easier cycle detection

Banker's Algorithm:

Works with multiple resource instances
Checks for safe state existence
More comprehensive detection

Prevention Strategies

Resource Ordering: Always request resources in same order
hX8: Release resources after hX8
xH4: Allow resource xH4
Avoidance: Use Banker's algorithm for allocation

How to Use

Select a detection algorithm from dropdown
Click Detect to run deadlock detection
Use Step to see algorithm execution step-by-step
Try Demo to see different deadlock scenarios
Click Reset to start with new configuration

Watch the Resource Allocation Graph and matrices to understand how deadlock detection works!