Stripping away the layers of abstractions: How does a filesystem work? (opens in new tab)

Modern operating system filesystems (like ext4 or NTFS) are intimidating to look at. If you dive into their source code, you're immediately drowned in millions of lines of C and endless layers of kernel abstraction. To demystify how bytes are actually mapped, tracked, and stored inside a physical file, I built TinyVFS, a filesystem that strips away the bloat so you can read the entire architecture in a single afternoon. Here is how it works under the hood, the architectural constraints I desi...