rsd0d or sd0d

[Cem Kayali <cemkayali%eticaret.com.tr@localhost>]

Hi,

Referrring to guide 
'http://www.netbsd.org/docs/guide/en/chap-misc.html#chap-misc-delete-disklabel'

I would like to delete disklabel of a usb disk and noticed that 
following command does not delete disk label + mbr though guide says it 
deletes:

dd if=/dev/zero of=/dev/rsd1d bs=1m


And once i tried following command, it deleted disklabel and mbr properly:

dd if=/dev/zero of=/dev/sd1d bs=1m


Is this what expected, and guide should be corrected? What is (should 
be) the differences between rsd0 and sd0 actually?


This is amd64 NetBSD5

Regards,
Cem