Virtual Memory Page Replacement Simulator

A C++ simulator for virtual memory management evaluating LRU and Second Chance page replacement algorithms using a Hashed Page Table.

Features

• Algorithms Supported:
  • LRU (Least Recently Used): Removes the page that hasn't been used for the longest time.
  • Second Chance (Clock): Uses reference bits to give recently used pages a second chance before replacement.
• Data Structures:
  • Custom Hashtable with chaining for the Hashed Page Table
  • std::unordered_map for fast $O(1)$ lookups
• Trace Processing: Reads real memory access traces (bzip.trace, gcc.trace).
• Statistics: Calculates total memory accesses, Page Faults, Disk Reads, and Disk Writes (handling dirty pages).

Build

Requirements

• C++11 (or higher)
• CMake 3.10+

Build Steps

mkdir build && cd build
cmake ..
make

Usage

Run the simulator from the project root directory so it can access the trace files:

./build/vm_simulator <algorithm> <num_frames> <q_max_chain> <max_references>

Command-Line Arguments

Parameter	Description
<algorithm>	1 for LRU, 2 for Second Chance
<num_frames>	Number of allocated physical memory frames (e.g., 100, 500, 1000)
<q_max_chain>	Maximum hash bucket chain threshold (e.g., 5)
<max_references>	Number of references to read (0 or leave blank for all)