ioctl equivalent to DIOCGSECTORSIZE in FreeBSD?

[Klaus Heinz <k.heinz%maerzehn.kh-22.de@localhost>]

Hi,

it looks like NetBSD does not have DIOCGSECTORSIZE (see
http://fxr.watson.org/fxr/source/sys/disk.h?v=FREEBSD8#L28).

In former times I would have tried to get a disklabel with DIOCGDINFO
and looked at d_secsize.

What is our official way nowadays to find out the size (in bytes) of a
sector?
Am I supposed to use DIOCGDISKINFO and plists?

I want to look at a disk attached to a USB port and I would like it to work
on NetBSD >=4.

ciao
     Klaus