Date: Thu, 16 Dec 1999 13:32:52 -0700 From: Warner Losh <imp@village.org> To: nate@mt.sri.com (Nate Williams) Cc: "FreeBSD Current Users' list" <freebsd-current@FreeBSD.ORG> Subject: Re: HEADSUP: ntp4 to replace xntpd Message-ID: <199912162032.NAA73759@harmony.village.org> In-Reply-To: Your message of "Thu, 16 Dec 1999 11:10:45 MST." <199912161810.LAA19919@mt.sri.com> References: <199912161810.LAA19919@mt.sri.com> <Pine.BSF.4.05.9912160934230.23583-100000@semuta.feral.com> <16818.945366687@critter.freebsd.dk>
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In message <199912161810.LAA19919@mt.sri.com> Nate Williams writes: : You may not know the answer to this, but it's worth a shot. Wht kind of : accuracy can we expect using 'cheap' off-the-shelf GPS receivers? We're getting, with ntp4 on a 3.x kernel, about +- 4uSec with a cheap gps receiver + atomic clock on a i486 class machine. The clock doesn't want to sync more closely than that, likely due to the large jitter in the 8254 timing device, so the atomic clock is a bit of a waste for this part of our application (there are others it is needed for). With a pentium class machine and w/o the atomic clock "backing", I'd say you could easily get into the sub-micro second range. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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