[ntp:questions] Is 24PPM an Excessive Real-Time Clock Correction?

Spoon root at localhost.invalid
Thu Jul 12 13:01:16 UTC 2007

Karel Sandler wrote:

> Spoon wrote:
>> I count at least 6 "clocks" on a typical x86-based platform:
>> o PIT (Programmable Interval Timer) e.g. Intel's 8253 and 8254
>> o RTC (Real-Time Clock)
>> o (Local??) APIC timer (not too sure about this one)
>> o ACPI timer, also known as PM (Power Management) clock
>> o CPU TSC (timestamp counter)
>> o HPET (High Precision Event Timers)
> how can I pick up and localize the clock the ntpd is based on
> (in order to measure the temperature of its crystal). The systems
> used are Linux or FreeBSD.

I have a pair of links that might be helpful:


Upgrading and Repairing PCs, 17th Edition states:
"A crystal oscillator controls clock speeds using a sliver of quartz 
sometimes contained in what looks like a small tin container. Newer 
systems include the oscillator circuitry in the motherboard chipset, so 
it might not be a visible separate component on newer boards."

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