> The problem with POSIX file APIs are the semantics in the presence of multiple concurrent writers. That sure is a problem with the file APIs, but far from th

> The problem with POSIX file APIs are the semantics in the presence of multiple concurrent writers. That sure is a problem with the file APIs, but far from the only one. Other issues include weird asynchrony, weird scatter/gather, lack of standard control over exposing parallelism to the device, broken fsync() and fdatasync() error semantics, just enough default buffering features to cause confusion but not avoid most performance bugs, lack of exposing device atomic write units, and many other things. It's an old API we've had for a long time. Made sense 40 years ago. But today it's just too low level to be easy, and too high-level to be fast.