Joseph Gray wrote: "I knew SNTP was not as good as NPT, but I would have thought that SNTP kept the clock accurate to at least the nearest second. Obviously not. So, what's the worst that a typical PC clock would be off when using SNTP?"
Truly, the answer is, "It depends." SNTP is designed to transfer the time from one machine to another with compensation for network travel time. It is precise if the network delay is symmetrical - same in both directions. This is seldom true. Even if the delay was symmetrical, your PC works with priority interrupts. A higher priority interrupt will destroy symmetrical network delay. The other source of error is the drift in your PC clock. NTP adjusts the clock frequency if you have an adjustable clock frequency, as is found in Unix derivatives. AFIK, a wintel clock frequency can't be adjusted. So the PC error depends on the frequency error and the rate at which the PC requests an SNTP update. I've found the Mount Hay Tech server to be able to keep a Win98 PC well within a second with hourly updates. YMMV. Regards, Bill Hawkins _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
