[ntp:questions] Re: Hardware clock fails to update.

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Fri Sep 15 07:25:05 UTC 2006

fmgrotepass at yahoo.co.uk (Frans Grotepass) writes:

> Our embedded system syncs with the server via NTP. The kernel (2.6.9) has RTC 
> set to UTC. When the system boots up, the hardware clock is off by 7200 
> seconds. When NTP syncs, the system time is set correctly and the system runs 
> synced for a decent while (2 hours). The system is then powered down and 
> restarted. Upon restarting, the clock returns to its 7200 second offset. 
> Various internet searches pointed to the fact that hardware clock syncing 
> being placed under the responsibility of ntp. Is this really the case? If so, 
> how can I check that NTP tries to update the hardware clock? 

Please try to read " How can I read or write the CMOS clock?" in the
NTP FAQ. The linux kernel does not write the full time back to the RTC AFAIK,
and other programs during startup/shutdown may be involved when messing with
the RTC chip.


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