ref.obs_zeroes revision 295749 
1295749Sthomas$FreeBSD: head/bin/dd/ref.obs_zeroes 295749 2016-02-18 08:44:16Z thomas $
2295749Sthomas00000000  41 42 43 44 45 46 47 48  00 00 00 00 00 00 00 00  |ABCDEFGH........|
3295749Sthomas00000010
4