On 2007-09-10, Rikishi 42 <[EMAIL PROTECTED]> wrote: > On 2007-09-09, Steve Kostecke <[EMAIL PROTECTED]> wrote: > >> ATTRIBUTION MISSING wrote: >> >>> ATTRIBUTION MISSING wrote: >>> >>>> ATTRIBUTION MISSSING wrote:
>> [NOTE: My configuration suggestions are at the bottom of this rather >> long article] > > Many thanks in advance, for the effort. The use of broadcast mode is important because it will allow the fixed systems on the LAN to notice the laptop within ~ 64 seconds after it is ready to be be a server. >>> The main concern is that that the laptop spends to much time >>> adjusting, correcting, etc... when it's only got a short time on the >>> ISP. >> >> Please define "too much time" and tell us why you think this is so. > > Well, that's not all that clear to me. Remember, I'm just posting > for someone else, here. :-) But I gather that he see's activity/log > entries/whatever going on a long time after he's returned home. If the laptop is not configured to use a drift file the initial synchronization after start-up is delayed by an additional 20 minutes or so. If the laptop is properly configured to use a drift file and has been allowed to run long enough (i.e. at least an hour) to allow the proper frequency correction value to be stored in the drift file, the initial synchronization on subsequent reboots should be extremely quick. >> I only [mentioned the dumb clock driver] because the nature of your >> application was unclear. > > Thanks for the info. Not to be rude, but the nature of the application > is clear to most that have allready answered. The fact that you're trying to sync a Time Island is abundantly clear. The reason for the existance of the Time Island was not. Sometimes it's not possible to connect a LAN to the outside world due to security or regulatory restrictions. sometimes the physical location precludes external connections or radio reception. It helps to know all the details when suggesting solutions. > But imagine this: <snip: passing the baton> > ... the shifts are numerous. That's due to the lack of a stable time base. > Only concern is: when the machines see the laptop, can they sync > realy, really fast, so that their NTP's work is done in a very short > lapse of time? In that case at least, the clocks would be within the > same second most of the time. You have two choices here: 1. Use broadcast mode as I've previously suggested. Doing so will allow the fixed systems to automatically detect the presence of the laptop within 64 seconds after it is connected to the LAN (and ntpd is ready to serve time). 2. Manually restart ntpd on all of the fixed systems after the laptop is connected to the LAN and ntpd is ready to serve time. Which ever solution you use, the fixed systems' clocks will be stepped if the offset between them and the laptop exceeds ~ 1/4 second. If the >> Then this is pointless exercise because you aren't really bringing >> anything back to the LAN. > > True from the point of view of someone intrested in precise time > keeping. I'm not taking an extremeist point of view >>>> 1. You need to have a drift file that contains an accurate >>>> frequency. >>> >>> Not an option for me, too fussy. >> >> It's a requirement. The drift file is where ntpd stores the correct >> frequency [correction] for the clock. > > Maybe. But since the problem seems to be the shift in time at every > boot/shutdown, is there any point in finding out what precise > frequency the system clock has? Would you prefer to have a clock that is a bit off _AND_ ticking at the wrong speed? The drift file helps get the the clock ticking at the "right speed" right at start up. >> If your OS is configured correctly, the system clock is saved to the >> hardware RTC during shut down. > > Boot a laptop several times, each time looking at it's time from > within the bios, wihout loading the OS. After enough reboots, you'll > see a error. Maybe today's laptops are better behaved, but I've had > machines loosing several seconds in a few days, when the OS didn't get > it's time sync'ed. My laptop is relatively new and runs ntpd. The system clock is initialized from the RTC at boot, ntpd syncs the clock, the system clock is stored to the RTC at shut down. I always see an initial step of more than 1 second when ntpd syncs. >> *** Configuration Suggestion > > Many, many thanks ! Please note that I omitted a line from the laptop ntp.conf file and posted a corrected version. -- Steve Kostecke <[EMAIL PROTECTED]> NTP Public Services Project - http://support.ntp.org/ _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
