Daniel Bernstein's page for clockspeed.

Daniel Bernstein's page on time and Unix.

David Mill's listing of secondary time servers for synchronizing with sntpclock.

Hompage for the U.S. Naval Observatory, Time Service Department. Lots of interesting links from this page. Read all about systems of time, leap seconds, and cesium fountains.

Current leap second information from the International Earth Rotation Service.

Frank Tegtmeyer's clockspeed setup page provided the basis for the clock_pick() function in the clockctl utility script.

The FreeBSD ports skeleton for clockspeed, possibly of interest for the patches which utilize the clock_gettime() functions. These may allow clockspeed to be ported to hardware other than Intel and Solaris.

By Dava Sobel, Walker & Co., 1995. The quest for precision timekeeping became an imperative for global navigation by the 18th century. This is a highly readable account of the challenges of the day, and describes the work of John Harrison (1693-1776), who made mechanical timepieces capable of remarkable accuracy.

By Eric Schlosser, Houghton Mifflin Company, 2001. Explains why the Earth is getting wobbly, out of balance, and spinning more slowly.