Messages in this thread | | | Date | Thu, 29 Jul 1999 07:29:00 +0000 | From | Steve Underwood <> | Subject | Re: [PATCH] HZ==100 assumptions |
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"Albert D. Cahalan" wrote:
> Eric Lammerts writes: > > On Wed, 28 Jul 1999, Riley Williams wrote: > > >> However, the standard used by MSDOS (which I assume is what you're > >> referring to) is for the clock to tick ~18.2 times per second (to > >> be more accurate, 65536 ticks per hour), in which case the correct > > > > This is incorrect. The BIOS/MSDOS clock is generated from a 14.31818MHz > > crystal clock divided by 12 * 65536. > > Nope. Clock frequency varies. Originally it was related to a standard > video frequency. More recent computers use a frequency designed to make > DOS timekeeping be more accurate. (the 65536 ticks/hour I suppose)
Nope. Many modern computers use an el. cheapo clock that is just plain inaccurate, and they don't keep time very well. Any Compaq ProLiant produced in the last 6 years keeps time to no better than plus or minus one to two minutes per day. Since these are generally used as servers, its a significant pain in the posterior - unless you are connected to the Internet, or have some other way to sync. the time of day to an external source.
In several stand alone systems I have had to use NTP to sync the Compaq machines to cheap no-name Taiwanese ones that are accurate to a few seconds per month. Silly, ain't it.
Steve
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