ntpd versus rtc

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Michael Tasche

ntpd versus rtc

Post by Michael Tasche » Thu Jan 24, 2008 3:34 pm

Hi all,

is it possible to let qnx ntpd interact with rtc?

My QNX System is not connected to the web all the time.
If ntpd has synchronized the system time from a time server in the web,
I want to set the rtc with this accurate time.
If the system is offline, I want to synchronize the system time with the
rtc.

Is this possible?
If yes, how to connect the rtc to the ntpd?
Must I provide a resource manager, providing something like "/dev/rtc"?

Thanks in advance
Michael

Mario Charest

Re: ntpd versus rtc

Post by Mario Charest » Thu Jan 31, 2008 2:03 am

"Michael Tasche" <michael.tasche@esd-electronics.com> wrote in message
news:gpnm65-l7p.ln1@comm.esd...
Hi all,

is it possible to let qnx ntpd interact with rtc?

My QNX System is not connected to the web all the time.
If ntpd has synchronized the system time from a time server in the web, I
want to set the rtc with this accurate time.
If the system is offline, I want to synchronize the system time with the
rtc.

Is this possible?
If yes, how to connect the rtc to the ntpd?
Must I provide a resource manager, providing something like "/dev/rtc"?
I'm not familliar with nptd but just setup a cron job to call "rtc -s hw" at
regular interval.
Thanks in advance
Michael

Kevin Miller

Re: ntpd versus rtc

Post by Kevin Miller » Fri Feb 01, 2008 8:40 pm

ntpd will "discipline" the system clock when the time server is not
available. It calculates the local clock error, and corrects for it in
between synchronizations. However, it does not do anything with the
hardware clock, which is why you have to do "rtc -s hw" periodically.

Mario Charest wrote:
"Michael Tasche" <michael.tasche@esd-electronics.com> wrote in message
news:gpnm65-l7p.ln1@comm.esd...
Hi all,

is it possible to let qnx ntpd interact with rtc?

My QNX System is not connected to the web all the time.
If ntpd has synchronized the system time from a time server in the web, I
want to set the rtc with this accurate time.
If the system is offline, I want to synchronize the system time with the
rtc.

Is this possible?
If yes, how to connect the rtc to the ntpd?
Must I provide a resource manager, providing something like "/dev/rtc"?


I'm not familliar with nptd but just setup a cron job to call "rtc -s hw" at
regular interval.

Thanks in advance
Michael

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