To be slightly more precise, sometimes you want the absolutely correct time
of day, and somtimes you want an accurately measured interval. This
distinction is key to good OS timekeeping, because you need to whack around
the ToD to correct for drift in your local system clock, but interval
timers must be inviolate (it would be evil to set a timer that never goes
off because the clock it ticks from got stepped beyond the firing time).

	Erik <fair@clock.org>