[ntp:questions] Re: NTP, Unix and the 34-year itch (better read this)
terje.mathisen at hda.hydro.com
Sat Jan 24 10:55:37 UTC 2004
David L. Mills wrote:
> I suspect you might have missed a previous message. Even if NTP steps
> the clock, it does not set it directly; the only operations allowed are
> to add or subtract something from the current time. Therefore, ntpd -g
> does have the same overflow problem whether or not the clock is nudged,
> stepped or stirred. Yes, I know deep down under the hood the actual time
> is handed off to Unix, but we don't allow customers to see that.
OK, that's the reason for my confusion then!
I've been looking at the NT port, where a big adjustment turns into an
explicit SetSystemTime call.
I do accept that this is in reality part of a Get + adjust + Set block.
> The primary motive for this design is that rollovers are transparent as
> long as you keep track of the hidden bits or reconstruct them from the
> file system. I need to say a few more words about that, but better said
> in an update of the web pages.
- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"
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