Subject: Re: settimeofday() versus interval tim{ers,ing}
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Erik E. Fair <>
List: tech-kern
Date: 09/30/1996 14:28:18
One of the cases worth worrying about, given the range of hardware that
NetBSD runs on, is systems whose TOD clocks are so *awful* that slewing the
clock just won't cut it all the time. Macintoshes come to mind, for some
reason. There are lots, unfortunately, of manufacturers who skimp on the
quality of the crystals they use for timers in the name of saving a few
more pennies per system.

Another example is an NTP-speaker on the wrong end of a congested Internet
link: NTP deals as best it can with that case, but there are limits to what
it can do; when the link uncongests, and a significant error is discovered,
it will step, not slew.

Having precisely the divorce between interval timers and Correct Time of
Day is a good thing, for all the reasons Dennis mentioned, and more. I
think he's had a terrific idea. This is good systems design.

	Erik E. Fair <>