EshaanOS

EshaanOS is a modular, educational operating system simulation written in C++. It provides a platform for experimenting with core OS concepts such as process scheduling, memory management, and virtual file systems. The project is designed for learning, research, and demonstration purposes.

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Features

• Process Scheduling

  • Implements multiple scheduling algorithms: FCFS (First-Come, First-Served) and SJF (Shortest Job First), with a flexible scheduler factory for extensibility.
  • CLI and test modules for creating, listing, and managing processes.
  • Real-time and batch simulation of process execution, including process states and metrics (waiting time, turnaround time, etc.).

• Memory Management & Paging

  • Simulates virtual memory, page tables, and physical memory.
  • Supports page replacement policies: FIFO (First-In, First-Out) and LRU (Least Recently Used).
  • Includes TLB (Translation Lookaside Buffer) simulation and memory usage statistics.
  • Test modules for page fault handling and frame replacement.

• Virtual File System (VFS)

  • Hierarchical file and directory structure with support for file creation, deletion, reading, and writing.
  • Directory and file abstractions with metadata (size, timestamps).
  • CLI and test modules for file system operations, including error handling and directory management.

• Command-Line Interface (CLI)

  • Interactive CLI for managing files, directories, processes, and memory.
  • Built-in help menus and command descriptions.

• System Monitoring

  • Tools for monitoring system state, processes, and memory usage.
  • Real-time display of processes, memory, and file system state.

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Architecture Overview

• Process Scheduling

  • EshaanOS_Scheduler.h, fcfs_EshaanOS_Scheduler.cpp, sjf_EshaanOS_Scheduler.cpp, and related headers define the scheduler interface and implementations.
  • SchedulerFactory creates scheduler instances based on the selected algorithm.
  • Process structures include fields for ID, name, arrival/burst time, priority, and state.

• Memory Management

  • memory_manager.h, page_table.h, physical_memory.h, and policy headers implement virtual memory, page tables, and page replacement.
  • MemoryManager handles page faults, frame allocation, and replacement using pluggable policies.
  • Test modules (memory_management_test.cpp, paging_simulation.cpp, etc.) demonstrate paging and replacement.

• Virtual File System

  • FileSystem.h, Directory.h, File.h, and their implementations provide a hierarchical VFS.
  • Supports nested directories, file metadata, and content management.
  • CLI and test modules (file_system_cli.cpp, vfs_cpp_test_all.cpp, etc.) provide user interaction and validation.

• CLI & Monitoring

  • cli_manager.cpp and system_monitoring.cpp implement interactive command-line interfaces for OS simulation and monitoring.

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Directory Structure

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├── cli_manager.cpp                # CLI management logic
├── Directory.*                    # Directory abstraction
├── EshaanOS_Scheduler*            # Scheduler interfaces and types
├── fcfs_EshaanOS_Scheduler*       # FCFS scheduling implementation
├── sjf_EshaanOS_Scheduler*        # SJF scheduling implementation
├── file_system*                   # File system core logic
├── File.*                         # File abstraction
├── FileSystem.*                   # File system interface
├── memory_management_*            # Memory management structures and tests
├── page_*                         # Paging and page replacement policies
├── process_*                      # Process management and scheduling
├── vfs_cpp_*                      # VFS operations (creation, deletion, reading, writing)
├── system_monitoring.cpp          # System monitoring utilities
└── ...                            # Additional modules and tests

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Getting Started

Prerequisites

• C++17 or later
• CMake (recommended) or a compatible build system
• A POSIX-compliant environment (Linux/macOS recommended)

Build Instructions

1. Clone the repository:

   git clone <repo-url>
   cd EshaanOS

2. Build the project:

   g++ -std=c++17 -o eshaan_os *.cpp

   Or use CMake for more advanced builds.

3. Run the simulation:

   ./eshaan_os

Running Tests

Test files are provided for various modules (e.g., ProcessEshaanOS_Scheduler_test.cpp, memory_management_test.cpp). Compile and run them individually:

g++ -std=c++17 -o test_process_scheduler ProcessEshaanOS_Scheduler_test.cpp
./test_process_scheduler

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Usage

• Process Scheduling:

  • Experiment with different scheduling algorithms by modifying the scheduler factory and running the relevant simulation files.
  • Use the CLI to create, list, and manage processes.

• Memory Management:

  • Simulate paging and page replacement by running paging_simulation.cpp or physical_memory_sim.cpp.
  • Test page fault handling and replacement policies with provided test modules.

• File System:

  • Use the CLI or VFS modules to create, read, write, and delete files and directories.
  • Explore directory management and error handling with test modules.

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Contributing

Contributions are welcome! Please open issues or submit pull requests for bug fixes, new features, or improvements.

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License

This project is licensed under the MIT License. See LICENSE for details.

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Acknowledgements

• Inspired by classic OS textbooks and university coursework.
• Thanks to all contributors and reviewers.

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Note: This project is for educational purposes and is not intended for production use.