readv(), writev()

[System Mangler]

In article <1035 at cit-vax.Caltech.Edu>, I write:
> On raw devices, physio() generates a physical I/O for each element
> of a readv() or writev().

I was wrong; only one I/O is generated, because readv() and writev()
on the raw device won't do more than a single iovec, due to bugs in
physio().  4.3bsd fixes one of the bugs, but there's still at least
one bug left:  writev() fails on the second iovec, with errno=ENXIO.

If readv() and writev() were useful, someone would have fixed this.

Don Speck   speck at vlsi.caltech.edu  {seismo,rutgers}!cit-vax!speck