The subject of "how to adjust your clock" is a real FAQ on this list.
I just ran across a "Clock mini-HOWTO" at <http://www.linuxdoc.org>. It seems to do a really excellent job of explaining the relations of the various hardware and software components concerned with time maintenance. I think it may shed some light into what still often seem dark corners of this subject. (BTW, apparently slink's xntp3 has been split into potato's ntp and ntpdate.) Experts feel free to jump in and criticize... Keith