The Network Time Protocol (NTP)  is used to keep a computer's clock synchronized with a set of time servers distributed over a network, each with varying accuracy and reliability.

This is very useful when you are using machines that share resources that have a timestamp associated with them. If one computer has a different idea of the time from another, strange errors can show up when using the shared resources. A good example is a file server and its clients. The shared resource are the files which almost always have timestamps associated with them.

Many of the latest versions of system software for all platforms include support for NTP servers. The HSC NTP time server is time.tamhsc.edu.