The CMOS clock on my Linux systems seem to lose time gradually and my favorite way to try to keep the time in sync is to perform regular time adjustments. I have a program I picked up several years ago called "nistime" that obtains a time string from the National Institute of Standard's atomic clock. I then have been having my systems do a "/sbin/clock -w" once a day when the daily cron job kicks off at 06:53 hours. This has helped keep my CMOS clocks much closer to actual time. Jim Osborn wrote:
Brad Shelton <bshelton@ole.ole.net> responds:
After you set the time, you need to write it to the hardware clock. Othwise it'll continue to get the wrong time from the hardware clock.
To set the hardware clock, as root do clock -w.
Thanks, Brad, and others. I guess it goes to show how long it's been since I've upgraded; my ancient Slackware setup wrote to the hardware clock whenever I did a simple `date.' I'd never heard of the `clock' or `hwclock' commands.
Another question occurs, though. In my previous setup, changes to/from Daylight Savings Time were automatic. I assume knowledge of these changes is in the Linux software, not the hardware clock, but in any case, I never had to perform any administrative tasks at that time of year. In fact, I could check with Linux if I was in doubt if this was the time of changeover.
Since I bought this machine just before last fall's change from DST, and I rarely reboot, I suspect SuSE 5.3 does NOT update the hardware clock after the DST change, but the normal Linux date routines know when the change occurs and adjust the soft clock, and that's why I didn't know anything was amiss.
What do you all recommend now to cope with DST? Should a routine be added somewhere to write to the hardware clock when a change to/from DST occurs, say, as a twice-a-year cron task? If so, does anyone have a favorite cron spec for USA DST?
I'm suspicious that my hardware clock is likely not very accurate, given that it seemed to be off noticably in the short time I halted my machine in my testing. What do you folks recommend as a source of accurate time? Is your computer crystal clock pretty good? Do you periodically dial up a standards bureau? Favorite suggestions? Given all the capabilities of clock(8) and hwclock it's tempting to go for some accuracy. My current /etc/adjtime is all zeros.
Thanks again,
Jim - To get out of this list, please send email to majordomo@suse.com with this text in its body: unsubscribe suse-linux-e Check out the SuSE-FAQ at <A HREF="http://www.suse.com/Support/Doku/FAQ/"><A HREF="http://www.suse.com/Support/Doku/FAQ/</A">http://www.suse.com/Support/Doku/FAQ/</A</A>> and the archiv at <A HREF="http://www.suse.com/Mailinglists/suse-linux-e/index.html"><A HREF="http://www.suse.com/Mailinglists/suse-linux-e/index.html</A">http://www.suse.com/Mailinglists/suse-linux-e/index.html</A</A>>
-- Anthony.Schlemmer@gte.net - To get out of this list, please send email to majordomo@suse.com with this text in its body: unsubscribe suse-linux-e Check out the SuSE-FAQ at <A HREF="http://www.suse.com/Support/Doku/FAQ/"><A HREF="http://www.suse.com/Support/Doku/FAQ/</A">http://www.suse.com/Support/Doku/FAQ/</A</A>> and the archiv at <A HREF="http://www.suse.com/Mailinglists/suse-linux-e/index.html"><A HREF="http://www.suse.com/Mailinglists/suse-linux-e/index.html</A">http://www.suse.com/Mailinglists/suse-linux-e/index.html</A</A>>