root wrote:

Bryce wrote:

If the CPU misses servicing the clock interrupt or other
bad stuff, the operating system's idea of time will
suffer, but the hardware clock keeps right on ticking.

So, if you're losing time without a reboot, the CMOS is
innocent and the O/S and CPU aren't doing the right
dance. If the time is wrong from the gitgo, then the HW
clock is the culprit.

Bryce

Good points. The computer loses time when it is running.
It is the way the time is updated by the cpu/kernel.
I am running linux.

Me too. Have a look at man hwclock.

Maybe running hwclock -r to resync the system time to the
CMOS (RTC) clock every so often as a cron job would suffice.
hwclock does tweaking to counter long-term drift in the RTC.
Not as spiffy as syncing with a time server, but no internet
connection needed.

Bryce