Haiku
From Richard's Wiki
- How to install Haiku to USB Flash Drive from Windows (If you get a message from Windows about not having permission to write to the USB drive, try taking it out and re-inserting it. Worked for me. Note this procedure of creating a bootable Haiku USB flash drive will DESTROY the entire drive, not just the first partition. Make sure there's nothing on the drive that you ever want to see again.)
- Programming the Be Operating System (O'Reilly Book, PDF)
- "Practical File System Design with the Be File System" (PDF, by the fellow who wrote the Be File System. Best to download it from the link directly.)