> It's also been suggested to me (by one of the authors of AudioFile)
> that the buffer (either fictitious, or, if possible, on the board
> itself) should be mmap(2)ed into the process, and system calls should
> only be used to request that blocks of data be input or output.  This
> would be somewhat more efficient than copyin()/copyout().

That is another approach.  But you'd still need some sort of
synchronization (or windowing) to avoid clicks/pops/dead-time.