Operating Systems Virtual Machine

Designed and implemented a Python-based virtual machine that simulates OS-level process execution, CPU scheduling, and memory management. The VM executes custom assembly-like programs at instruction-level granularity and supports multiple scheduling algorithms with detailed performance visualization.

Key Contributions:

• Implemented a virtual CPU executing one instruction per tick with full instruction decode and execution pipeline.
• Designed a flat byte-addressable memory model and extended it with a paging-based MMU.
• Built full process management using PCBs tracking PID, state, registers, program counter, execution time, and wait time.
• Implemented and validated multiple CPU scheduling algorithms: — First-Come First-Serve (FCFS) — Round Robin (preemptive, configurable quantum) — Multi-Level Feedback Queue (MFQ) with aging, promotion, and demotion
• Implemented paging and page-fault tracking, including logical address spaces, frame allocation, eviction, and MMU integration.
• Generated Gantt charts and performance visualizations to analyze scheduling behavior, wait times, and page fault trends across workloads.
• Built a shell interface for loading programs, running simulations, and debugging execution (core dumps, error dumps).