Clock Error
All system clocks have common properties that contribute to clock error and interfere with the synchronization process. System clock error tends to increase over time; the rate of change of error is known as drift. If each system clock in a network started at the same time and ran at the same rate, the clocks would remain synchronized. Because each system clock drifts at a different rate, however, the system clocks throughout a network become desynchronized.
The difference between any two clock readings is known as the skew between the clocks. The clocks that are used in many computer systems have a specified maximum drift of a few seconds per day. If uncorrected for several days, the skew between networked system clocks can inhibit the performance of distributed applications.
The DTS server or clerk on each node tracks the drift of its client's system clock and periodically synchronizes with other DTS nodes to reduce the skew between its client's time value and those of the other DTS nodes. The DTS server or clerk adjusts the system clock on its client node as the final step in this repeating synchronization process.