>From what I gather, the various Unix (and NT) sendfile-ish
> calls are not internally compatible, so I am not sure how to
> handle compatibility, but I think having the real call be move(2)
> (or perhaps copy(2)) would be really nice.

I'd vote for something less ubiquitous though (both "move" and "copy"
have other meaning normally), what about sendfdto(2)
(a la sendto(2)) ?

How big is performance improvement of sendfile() over equivalent
user space code ?

Jarda