OS Simulator (Java)

Engineered by Yug Arora

A modular Operating Systems (OS) simulator written in Java.

It contains small, focused implementations of classic OS topics (CPU scheduling, paging, memory allocation, disk scheduling, synchronization, deadlock detection) with a CLI to run demos and an analysis layer to compare results.

What’s inside

Algorithms & demos

• CPU Scheduling: FCFS, Round Robin (+ Gantt-style output)
• Paging: FIFO, LRU (+ step-by-step logs)
• Memory Allocation: First Fit, Best Fit, Worst Fit (+ compaction + fragmentation metrics)
• Disk Scheduling: FCFS, SSTF, SCAN, C-SCAN (+ head-movement graph)
• Synchronization: Producer–Consumer, Readers–Writers, Dining Philosophers (thread-based)
• Deadlock: Resource Allocation Graph → Wait-For Graph, cycle detection

Extras

• cli/ menu-driven scenarios
• analysis/ metrics + comparison reports + CSV exporter

Project structure

• cli/ — interactive menu + scenario runner
• scheduling/ — FCFS, Round Robin
• paging/ — FIFO, LRU + comparators/formatters
• memory/ — allocators + reports/validation
• disk/ — disk schedulers + comparison + graphs
• synchronization/ — semaphore + classic synchronization problems
• deadlock/ — RAG/WFG + deadlock detector
• analysis/ — metrics + report/CSV export
• models/, utils/ — shared data models and helpers

Quickstart (Windows PowerShell)

Prerequisites

• JDK (Java) installed (javac and java available in PATH)

Build (run from the project root)

javac -d bin .\Main.java `
  .\models\*.java `
  .\utils\*.java `
  .\scheduling\*.java `
  .\paging\*.java `
  .\memory\*.java `
  .\disk\*.java `
  .\synchronization\*.java .\synchronization\producerconsumer\*.java `
  .\synchronization\readerswriters\*.java .\synchronization\philosophers\*.java `
  .\deadlock\*.java `
  .\analysis\*.java `
  .\cli\*.java

Run the CLI

java -cp bin cli.Application

Example runs (direct entry points)

java -cp bin Main
java -cp bin paging.PagingComparison
java -cp bin memory.MemoryValidation
java -cp bin disk.DiskComparison
java -cp bin synchronization.producerconsumer.ProducerConsumerSimulator
java -cp bin synchronization.readerswriters.ReadersWritersSimulator
java -cp bin synchronization.philosophers.DiningPhilosophersSimulator

Documentation

• Architecture overview: see ARCHITECTURE.md

Notes / troubleshooting

• Run commands from the project root so -cp bin resolves correctly.
• Disk scheduling assumes track indices are in the range 0 to diskSize - 1.
• Synchronization demos are thread-based, so output ordering may interleave.