David Woolley wrote: > Richard B. Gilbert wrote: > >> The clock in a PC is basically the guts of a cheap "Quartz" watch. It >> wouldn't surprise me if the manufacturers bought the crystals rejected >> by the watch makers. I suspect that the clock exists MOSTLY so the >> machine will have the correct date for things like letters and checks. > > That describes the RTC, and may not even be valid for HPET systems. The > clock that ntpd disciplines is not based on a 32kHz watch crystal, but > on a much higher frequency crystal. Historically, the primary purpose > of the latter crystal is to provide a logic clock for the processor and > memory, not for time keeping.
And it probably varies in frequency with temperature and age. And probably no one cares if the frequency is off by a percent or two, especially if it's off on the high side. Who is going to complain if his 2.4 GHz processor is actually operating at 2.45 GHZ?? _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
