D. J. Bernstein


clockspeed is discussed on the libtai mailing list.

The latest published clockspeed package is clockspeed-0.62.tar.gz.

What is it?

clockspeed uses a hardware tick counter to compensate for a persistently fast or slow system clock. Given a few time measurements from a reliable source, it computes and then eliminates the clock skew.

sntpclock checks another system's NTP clock, and prints the results in a format suitable for input to clockspeed. sntpclock is the simplest available NTP/SNTP client.

taiclock and taiclockd form an even simpler alternative to SNTP. They are suitable for precise time synchronization over a local area network, without the hassles and potential security problems of an NTP server.

This version of clockspeed can use the Pentium RDTSC tick counter or the Solaris gethrtime() nanosecond counter.

Typical success story: I started clockspeed on one of my Pentium computers at home on 1998-05-05. I ran sntpclock (through a 28.8 dialup line) once on 1998-05-05 and once on 1998-05-30. On 1998-08-22, after no network time input for nearly three months, the clock was just 0.21 seconds off.