Re: Why touch the CMOS clock?

Mark Eichin (eichin@athena.mit.edu)
15 May 1996 23:47:50 -0400


> RTC doesn't drift quite that much when the system is off, but it does
> drift enough that I have to check the clock if I have the system off for

The RTC is driven by a crystal. Crystals are temperature change
sensitive; I think the temperature sensitivity is quadratic. Look in
ftp.udel.edu pub/ntp (ie. along with the ntp sources) for the
time-surveying paper and figures -- an MIT thesis project on clock
quality and synchronization came up with a lot of interesting things
about the real world properties of clocks.