osdev-filesystems

What problem does it solve?

Kernel and bare-metal developers face complex, low-level challenges when implementing file I/O: parsing on-disk formats, mapping block pointers to logical data, and exposing a uniform interface to higher layers. This Skill consolidates reference material and practical guidance to avoid common parsing errors, incorrect pointer math, and fragile directory handling.

Core Features & Use Cases

• VFS Design: Clear abstractions for superblock, inode/vnode, dentry, file, and mount table with operation interfaces.
• FAT12/16/32 Implementation: BPB parsing, FAT table handling, cluster chain walking, directory entry parsing, and long filename reconstruction.
• ext2 Reader: Superblock and block group layout, inode layout and indirect pointer resolution, directory entry walking, and path-to-inode resolution.
• Practical Use Cases: Writing a bootloader or kernel module that loads a kernel from a FAT partition, implementing a read-only ext2 driver for an embedded device, or adding a new filesystem driver into an existing VFS.

Quick Start

Implement a FAT32 and ext2 reader for a bare-metal kernel that parses the BPB, resolves cluster chains and inodes, reconstructs long filenames, and registers the filesystem operations with your VFS.