Free Space Management in File System Implementation

When a file is created or expanded, how does the operating system instantly find empty space on a drive? Understanding free space management is critical for building efficient, reliable storage engines and low-level software. This text-only course guides you through the core algorithms and structures that file systems use to keep track of available storage. You will start with the fundamental terminology of blocks, sectors, and inodes before diving into concrete implementation strategies. What you will learn: Understand the foundational concepts of disk block allocation and storage layouts; Implement and analyze bit-vector (bitmap) approaches for tracking free blocks; Compare linked list and grouping strategies for tracking empty sectors; Analyze indexing techniques like B-trees and modern extent-based allocation; Trace how filesystems prevent fragmentation and maintain performance over time. You will begin with basic disk block concepts and progress systematically to complex allocation strategies, evaluating the trade-offs of each approach through clear, written explanations and pseudo-code examples. This course is designed for beginner software engineers, computer science students, and systems enthusiasts who want to understand the low-level mechanics of storage. No prior operating systems design experience is required. Start reading to master the inner workings of file system storage management.