Memory Management

Module Overview

Welcome to the heart of the Operating System. Memory Management is the magic that allows your 16GB laptop to run 100GB worth of applications simultaneously. It is a complex dance between hardware (MMU, TLB) and software (Kernel) to create the “Virtual Memory Illusion.”

In this module, we will deconstruct how the OS manages RAM, one byte at a time. We will move from the hardware level (Page Tables) to high-level algorithms (LRU Eviction) and finally to user-space allocation (malloc).

Learning Objectives

  • Hardware Reality: Understand how the MMU translates Virtual Addresses to Physical Addresses.
  • Paging Mechanics: Deep dive into Multi-Level Page Tables (PML4) and the TLB.
  • Performance: Analyze Page Replacement Algorithms (LRU, Clock) and the cost of Swapping.
  • Stability: Diagnose Thrashing and understand the Working Set Model.

  • Allocation: Implement your own memory allocator and understand Heap fragmentation.

Memory Management

[!NOTE] This module explores the core principles of Memory Management, deriving solutions from first principles and hardware constraints to build world-class, production-ready expertise.

1. Chapter Roadmap

  1. Virtual Memory The “Great Lie” of the OS. How every process thinks it owns 100% of the RAM, and how the MMU maintains this illusion using address translation.

  2. Paging vs Segmentation The evolution of memory division. Why modern systems chose Paging over Segmentation, and how Multi-Level Page Tables save space.

  3. Page Replacement Algorithms When RAM is full, who gets kicked out? We compare FIFO, LRU, and the Clock Algorithm to minimize page faults.

  4. Thrashing & Working Sets The “Spiral of Death.” What happens when processes demand more memory than exists, and how the Working Set Model prevents system collapse.

  5. Memory Allocation How malloc actually works. We explore Heap management, Free Lists, Slab Allocation, and the Buddy System.

2. Interactive Labs

  • MMU Translator: Manually translate Virtual Addresses to Physical Addresses.
  • Page Table Walker: Step through a 4-level Page Table lookup.
  • Eviction Simulator: Pit LRU against FIFO in a live simulation.
  • Thrashing Monitor: Watch a system grind to a halt as Working Sets exceed RAM.
  • Allocator Visualizer: Manage a Heap and see fragmentation in real-time.

Module Chapters