VM Simulation

A C program I developed to simulate virtual memory management systems, implementing various page replacement algorithms. This project provides a practical understanding of how operating systems handle memory management and page faults.

What It Does

• Simulates virtual memory management with configurable parameters
• Implements three page replacement algorithms:
  • OPT (Optimal)
  • NRU (Not Recently Used)
  • CLOCK
• Tracks detailed memory access statistics
• Handles page faults and disk writes

How It Works

The program reads memory access traces and simulates how different page replacement algorithms handle memory management. It maintains a page table and tracks various statistics like page faults and disk writes.

// Example of page table entry structure
struct page_table_entry {
    int valid;
    int ref;
    int dirty;
};

// Example of memory access processing
void process_trace_file(FILE *f) {
    // Read trace file line by line
    while (fgets(line, sizeof(line), f) != NULL) {
        struct tuple mem_access = sanitize_trace_line(line);
        int page_number = get_page_number(mem_access.add);
        
        // Handle page faults and replacements
        if (!page_table[page_number].valid) {
            page_faults++;
            // Implement replacement algorithm
        }
    }
}

Technical Bits

• Written in C for performance
• Uses bitwise operations for address translation
• Implements circular linked lists for CLOCK algorithm
• Handles memory allocation and deallocation
• Processes memory trace files

Why I Built It

I wanted to understand how operating systems manage virtual memory and how different page replacement algorithms affect system performance. This project helped me gain insights into low-level memory management concepts.

Future Ideas

• Add more page replacement algorithms
• Implement memory access pattern analysis
• Add visualization of memory usage
• Support for different page sizes
• Performance comparison between algorithms