On Thursday 06 December 2007 17:38, Carlos E. R. wrote:
The Thursday 2007-12-06 at 17:26 -0800, Randall R Schulz wrote:
On Thursday 06 December 2007 17:16, Carlos E. R. wrote:
...
Please, remember that the system time does not use the cmos clock and battery at all. ...
"... at all ...?" I don't think this is really true, is it?
When the system starts up, ...
I know that. I actually wrote a howto on that ;-)
What I mean is that during normal system use it is not used at all. It is read on boot, and written on halt (and I think on NTP stop, by the script, not the daemon).
Thereafter, the Linux kernel updates its time based on a timer interrupt, also generated by local hardware, of course. These timers are, as has been noted, not particularly accurate and often exhibit considerable drift over even moderate real-time intervals.
Not really. I have been using this same machine without permanent network, and thus, no NTP, for years, and the clock drift was about a second or two per day.
Then you have the luck of getting a pretty good crystal. That's just a matter of luck. One second per day is 0.0000116 or 0.00116% error.
Likewise, if the system cannot contact an NTP server, it has a reasonable guess as to the current time, and it makes do with that.
It should be able to keep accurate time for hours, even days. This was so with previous suse versions, but not with 10.3. It drifts minutes in half an hour. This is unthinkable!
Clearly this represents a gross hardware failure or a similarly extreme software problem. You might want to try to quantify the error to a few decimal places. I had an early instance of the very first Macintosh, and it had a similarly excessive clock drift problem. I don't remember the details now (it was twenty-some years ago) but I realized that the problem was something like every 2^8 seconds it added a second. Since 2^8 seconds is only 4 minutes 16 seconds, this was a very blatant error! But the real point was that it was clear that a single-bit glitch on a predictable interval was responsible for the empirical error I witnessed.
-- Cheers, Carlos E. R.
Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org