Notes for the dd command
========================

If direct i/o is available, dd also includes two undocumented flags
'conv=idirect' and 'conv=odirect' which enable direct i/o on input
and output, respectively. Use conv=odirect with care as it requires
padding for correct operation; write() will fail with EINVAL if a
request is not a multiple of an acceptable buffer size. This will
happen in particular at the end of a file. Using conv=odirect thus
usually requires conv=sync and cannot be used if such padding will
destroy the file integrity.

        Gunnar Ritter                                           4/5/04
