Virtual Memory Manager Simulator

A comprehensive C-based simulator for virtual memory management systems featuring multiple page replacement algorithms, TLB simulation, and working set analysis.

🚀 Features

Core Page Replacement Algorithms

• FIFO (First In, First Out) - Simple queue-based replacement
• LRU (Least Recently Used) - Optimal for temporal locality
• Optimal Algorithm - Theoretical best performance benchmark
• Clock Algorithm - Efficient approximation of LRU with dirty bit support

Advanced Features

• TLB (Translation Lookaside Buffer) Simulation

  • Configurable hit/miss ratios
  • Address translation performance tracking
  • Memory access time calculations

• Working Set Analysis

  • Locality pattern detection
  • Frame allocation optimization
  • Memory utilization metrics

• Belady's Anomaly Detection

  • Automated test case generation
  • Statistical analysis of anomaly occurrences
  • Performance comparison across frame sizes

📊 Output and Analysis

Console Output

=== Virtual Memory Simulation Results ===
Algorithm: LRU
Frames: 4
Sequence Length: 20

Page Faults: 15
Hit Ratio: 25.00%
Miss Ratio: 75.00%

=== TLB Statistics ===
TLB Hits: 16
TLB Misses: 4
TLB Hit Ratio: 80.00%
Average Access Time: 1.4 ns

=== Working Set Analysis ===
Average Working Set Size: 3.2
Locality Score: 0.65
Recommended Frames: 4

📈 Algorithms Implemented

1. FIFO (First In, First Out)

• Simple queue-based replacement
• O(1) replacement decision
• Susceptible to Belady's anomaly

2. LRU (Least Recently Used)

• Uses timestamp-based tracking
• Optimal for temporal locality
• O(n) time complexity for updates

3. Optimal Algorithm

• Looks ahead in reference string
• Theoretical minimum page faults
• Used as performance benchmark

4. Clock Algorithm

• Circular list with reference bits
• Dirty bit support for write-back
• Efficient approximation of LRU

🔍 Working Set Analysis

The simulator performs working set analysis to:

• Detect memory access patterns
• Identify locality of reference
• Recommend optimal frame allocation
• Track memory utilization over time

⚠️ Belady's Anomaly Detection

Automated detection system that:

• Generates test cases across different frame sizes
• Identifies cases where more frames result in more page faults
• Provides statistical analysis of anomaly frequency

📋 Sample Test Cases

Test Sequence 1 - High Locality

1 2 3 4 1 2 5 1 2 3 4 5

Test Sequence 2 - Random Access

7 0 1 2 0 3 0 4 2 3 0 3 2

Test Sequence 3 - Sequential Access

1 2 3 4 5 6 7 8 9 10 11 12