What I wanted to say is that mmap may be faster from such point of view but that difference may not make observable impact especially for application like audioplay(1).For audioplay(1), yes, I agree. That is an example of an application for which the performance differences are minor enough to be easily outweighed by the convenience. I doubt anyone would argue that the write() interface should go away.
I agree too but I needed to implement mmap use (userspace) somewhere to make my point. I think audioplay is still a right choice (even if it does not improve it) because it shows how to implement it as it it always included in netbsd. I personnally never
use audioplay to play audio..