StepAlgo

StepAlgo is an Electron desktop application for visualizing classic operating-system page-replacement algorithms. It lets users enter or generate a page-reference string, choose the number of page frames, and compare FIFO, LRU, and Optimal replacement behavior through an interactive simulation.

Table of Contents

• Preview
• Tech Stack
• Repository Overview
• Features
• Installation Guide
• Usage
• Algorithm Comparison Design
• Documentation Assets
• Constraints and Future Improvements
• License

Preview

Preview	Description
	Main simulation workspace for entering a reference string, setting frame count, running calculations, and comparing page-fault totals across FIFO, LRU, and Optimal.
	Educational reference screen explaining the algorithms, complexity notes, and glossary terms used in the simulation.

Tech Stack

Technology	Role
Electron	Provides the desktop shell, application window, native menu, and packaging target.
JavaScript	Implements reference-string generation, input validation, page-replacement simulation, page-fault counting, and UI updates.
HTML	Defines the computation and information screens.
CSS	Styles the desktop interface, algorithm panels, controls, glossary, and visual output grid.
Node.js and npm	Manage the development runtime, scripts, dependencies, and lockfile.
electron-builder	Builds distributable desktop packages for macOS, Windows, and Linux.
XO and ESLint	Provide the configured linting/test command used by the project and CI workflow.

Repository Overview

.
├── index.js                  # Electron main process and BrowserWindow setup
├── index.html                # Main page-replacement computation interface
├── renderer.js               # Simulation logic for FIFO, LRU, and Optimal
├── information.html          # Educational reference and glossary screen
├── information.js            # Glossary navigation and view interactions
├── index.css                 # Main computation view styling
├── information.css           # Information view styling
├── menu.js                   # Electron application menu configuration
├── config.js                 # electron-store configuration wrapper
├── images/                   # README and project screenshots
├── documentation/            # Supporting operating-systems case-study PDFs
├── icons/, logo/, static/    # App icons and interface assets
├── package/                  # Packaged release snapshot
└── package.json              # Scripts, dependencies, and electron-builder config

Features

• Visualizes FIFO, LRU, and Optimal page-replacement algorithms under the same workload.
• Accepts custom comma-separated reference strings with values from 0 to 9.
• Generates random page-reference strings with configurable length.
• Supports page-frame counts from 1 to 9.
• Rebuilds the simulation grid dynamically based on the reference-string length.
• Highlights page-fault events in each algorithm's frame history.
• Calculates and compares total page faults for each algorithm.
• Recommends the most efficient algorithm for the current input, including tie handling.
• Includes an information screen with algorithm explanations, complexity notes, and glossary navigation.

Installation Guide

Prerequisites

• Node.js 18 or newer
• npm

Setup

1. Clone the repository:

   git clone https://github.com/shoichiideologies/page-replacement-algorithm.git
   cd page-replacement-algorithm

2. Install dependencies:

   npm install

3. Start the desktop app:

   npm start

Usage

1. Enter the number of page frames to allocate.
2. Enter a comma-separated reference string, or use the random button to generate one.
3. Adjust the reference length when generating random inputs.
4. Select Calculate to run FIFO, LRU, and Optimal against the same input.
5. Review the visual frame history, page-fault totals, and recommendation summary.

Development Commands

Command	Description
npm start	Runs the Electron app locally.
npm test	Runs the configured linting check through XO.
npm run lint	Runs XO directly.
npm run pack	Creates an unpacked local Electron build.
npm run dist	Builds distributable packages for configured platforms.
npm run dist:mac	Builds a universal macOS package.

Algorithm Comparison Design

The simulator is designed around side-by-side comparison rather than isolated algorithm demonstrations. Each calculation uses the same reference string and frame count for FIFO, LRU, and Optimal, then renders separate frame histories and page-fault counts.

The Optimal implementation uses future knowledge as a benchmark and selects the first available page when multiple loaded pages will never be used again. That deterministic tie-break keeps repeated runs predictable while still demonstrating the theoretical lower bound for page faults.

When multiple algorithms produce the same minimum page-fault count, the app reports the tie and chooses a practical recommendation. If all three algorithms tie, LRU is preferred because it avoids Optimal's unrealistic future knowledge while generally modeling real-world locality better than FIFO.

Documentation Assets

The documentation/ directory contains supporting PDFs for the operating-systems case study behind the project, including the broader virtual-memory topic and page-replacement-specific material. These files are useful for understanding the academic context and terminology reflected in the information screen.

Constraints and Future Improvements

• The simulator currently focuses on FIFO, LRU, and Optimal; additional algorithms such as Second Chance, Clock, LFU, or MRU could broaden the comparison.
• Reference-string values are limited to single-digit pages from 0 to 9, which keeps the interface compact but limits larger demonstrations.
• The main Electron window is fixed at 1500x900, so responsive behavior could be improved for smaller displays.
• The app includes desktop packaging scripts, but release metadata and menu links still contain boilerplate values that should be customized before public distribution.
• Simulation output could be expanded with step-by-step playback, annotations, exportable results, and saved scenarios.
• Accessibility can be improved with stronger keyboard workflows, focus states, and screen-reader-oriented descriptions for the generated simulation grid.

License

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