Memory Allocation Simulator — Segmentation

A professional desktop application that simulates Memory Allocation using Segmentation, built for Operating Systems coursework.

Features

• Segmentation-based memory management with real-time visualization
• Two allocation algorithms: First Fit & Best Fit
• Dynamic process creation with configurable segments
• Automatic hole merging on deallocation
• Rollback support — if any segment fails, entire allocation is undone
• Three-panel GUI: Controls | Memory Map | Data Tables
• Dark modern theme with smooth, professional styling
• Live statistics: total/used/free memory, fragmentation percentage
• Export screenshots of the memory visualization
• Complete input validation and error handling

Memory Visualization

Each memory block displays:

• Segment name and owning process
• Start and end addresses
• Block size in KB
• Color coding: purple/blue/green for processes, gray dashed for holes, dark for reserved

Technology Stack

Component	Technology
Language	Python 3.10+
GUI Framework	PySide6 (Qt 6)
Packaging	PyInstaller
Architecture	Clean OOP (MVC-like)

Project Structure

memory assignment/
├── main.py                  # Application entry point
├── requirements.txt         # Python dependencies
├── test_cases.py            # Automated test suite (10 tests)
├── build_exe.py             # Standalone EXE build script
├── README.md                # This file
├── models/                  # Data model classes
│   ├── __init__.py
│   ├── segment.py           # Segment (name, size, base address)
│   ├── process.py           # Process (name, list of segments)
│   ├── hole.py              # Hole (start address, size)
│   └── memory_block.py      # MemoryBlock + BlockType enum
├── core/                    # Business logic engine
│   ├── __init__.py
│   └── memory_manager.py    # MemoryManager (allocation, deallocation, merging)
└── gui/                     # GUI layer
    ├── __init__.py
    ├── styles.py            # Dark theme QSS stylesheet
    ├── memory_view.py       # Custom memory visualization widget
    └── main_window.py       # Main application window

Installation & Running

Prerequisites

• Python 3.10 or newer
• pip package manager

Setup

# 1. Install dependencies
pip install -r requirements.txt

# 2. Run the application
python main.py

# 3. (Optional) Run tests
python test_cases.py

Building Standalone EXE

# Generate a standalone executable
python build_exe.py

The executable will be created in the dist/ folder. You can distribute it without requiring Python to be installed.

Manual PyInstaller command

pyinstaller --onefile --windowed --name "MemoryAllocSimulator" main.py

Allocation Algorithms

First Fit

Scans holes in address order and allocates the segment to the first hole large enough to hold it.

• Advantage: Fast — stops at the first suitable hole.
• Disadvantage: Tends to fragment the beginning of memory.

Best Fit

Scans all holes and selects the smallest hole that can fit the segment.

• Advantage: Minimizes wasted space per allocation.
• Disadvantage: Slower scan; can produce many tiny unusable holes.

Rollback Mechanism

If a process has multiple segments and any segment cannot be allocated, the entire process allocation is rolled back — all partially allocated segments are freed and holes are restored to their pre-allocation state.

Run them: python test_cases.py

Authors

• Operating Systems Course — University Project

License

This project is for educational purposes.