Microsoft tried this with Windows Future Storage: https://en.m.wikipedia.org/wiki/WinFS https://en.m.wikipedia.org/wiki/WinFS OS/400 is quite different too:

Microsoft tried this with Windows Future Storage: https://en.m.wikipedia.org/wiki/WinFS https://en.m.wikipedia.org/wiki/WinFS OS/400 is quite different too: https://www.quora.com/On-the-AS-400-how-are-objects-stored-on-a-disk-compared-to-a-traditional-filesystem-like-FAT32-or-ext4-Whats-the-underlying-filesystem-like https://www.quora.com/On-the-AS-400-how-are-objects-stored-o... The BeOS filesystem has many DB like features: https://en.m.wikipedia.org/wiki/Be_File_System https://en.m.wikipedia.org/wiki/Be_File_System