On Thu, Nov 29, 2001 at 04:21:46PM +0100, Maciej W. Rozycki wrote: > > Better stick with the calibration procedure. The crystal oscilators used > > in most computer systems don't provide the high accuracy of frequency > > that is required to keep the clock accurately over long time. An RTC > > chip which you'd probably use as reference clock is better at that so > > should be used as the ultimate reference time in the kernel. > > On the contrary, the DECstation's undocumented I/O ASIC FCR (free running > counter) driven by the TURBOchannel bus clock is said to be much more > accurate than the DS1287 used there. And it's David L. Mills who says so, > thus we may safely assume it's true. :-) Whooa, Master Secundus Minutius Hora himself ;-) Actually the accuracy of crystal oscillators may differ wildly depending on the use in a system and environmental conditions. In case of the SGI Indy the DS1387 RTC (which is rated at +/- 25ppm ~= 1 minute / month) is actually more accurate. Ralf
