OS Simulation Suite

Overview

From August to December 2024, I built a compact suite of operating system simulations in modern C++. The suite spans four core OS topics—linking/loading, CPU scheduling, memory paging, and disk I/O scheduling—with a clean, modular design, deterministic drivers, and full reproducibility.

Tech & Structure

• Language & style: C++ (modular .h / .cpp), clear separation of concerns
• Organization: Four lab directories (Module1 through Module3), each containing drivers, simulators, policies, and test scripts
• Reproducibility: Makefiles, runit scripts, and fixed random number input datasets under rfile/ to enforce deterministic behavior

Modules

Module 1 — Linker / Loader

• Features: Two-pass linker implementing symbol resolution, relocation, error detection (duplicate symbols, out-of-bounds sections, unused symbols)
• Output: Memory maps, symbol tables, diagnostic logs

Module 2 — CPU Scheduling

• Features:
  • Simulates process arrival, CPU/IO bursts, preemption
  • Supports FCFS, SJF, SRTF, Round-Robin, Priority
• Outputs: Per-process finish time, turnaround, waiting time; system-level usage & throughput

Module 3 — Memory Management (Paging / MMU)

• Approach:
  • Parses VMAs and memory-access traces
  • Implements replacing policies: FIFO, Random, Clock, Aging, Working-Set
  • Maintains frame table, PTE states (present, referenced, modified)
• Outputs: Page faults, maps/unmaps, ins/outs, zeros, total time

Module 4 — Disk I/O Scheduling

• Features: Simulated policies - FIFO, SSTF, LOOK, C-LOOK, FLOOK via discrete-event simulation of head motion (1 track/time unit), queued requests, starvation avoidance
• Outputs: Head movement counts, request turnaround and wait times, utilization metrics

Highlights & Outcomes

• Event-driven architecture with plugable policy interfaces — easy to swap in/out scheduling, paging, I/O strategies
• Deterministic runs via fixed seeds and driver scripts produce repeatable experiments
• Rich metrics & logs that follow textbook OS definitions, used for benchmarking, correctness, and grading
• Cohesive stack: The suite ties together linking, CPU scheduling, memory, and I/O into a unified, testable OS simulation environment

Code Availability

To view the complete code for this simulation suite, please contact me directly