The way BeOS used filesystem attributes like a database was way ahead of the curve and it still might be. This book was a great read back in the day of what go

The way BeOS used filesystem attributes like a database was way ahead of the curve and it still might be. This book was a great read back in the day of what goes into a "modern" filesystem design https://archive.org/details/practical-file-system-design "Practical File System Design" was technical but also readable. Straight from the man who designed BFS which makes it more of an accomplishment IMO.