Unix Kernel Modifications for Precision Time Synchronization
In the 1994 report Unix Kernel Modifications for Precision
Time Synchronization, David L. Mills provides a substantial revision of RFC 1589. It includes several changes to the daemon and user interfaces, as well as a new feature which disciplines the CPU clock oscillator in both time and frequency to a source of precision time signals, as well as provisions to operate with good accuracy at much higher poll intervals in the order of several hours.