This morning I noticed that the clock on the linux computer was off by five minutes. I had not adjusted it in months, and I suppose it simply drifted that much. To prevent the problem from recurring, I installed a Network Time Protocol Daemon, which periodically queries remote computers for the time. They are known as "stratum 2" machines, and they are synchronized with "stratum 1" machines, which are synced to GPS satellites, atomic clocks, etc. The NTP daemon is able to measure the systematic drift in the clock and compensate for it; some temperature-dependent drift may still occur. The period of polling other computers is initially about 64 seconds and gradually increases to about 1024 seconds (or whatever you set it to). I understand the accuracy associated with using NTP is around 50ms.
Posted by seander at April 22, 2004 10:59 PM