* Paul de Weerd <[EMAIL PROTECTED]> [2007-10-24 19:28]: > On Wed, Oct 24, 2007 at 10:47:45AM -0500, Boris Goldberg wrote: > | May be it makes sense to set "-ncv" as a default behavior of rdate, but > | there is should be a way to synchronize time without running a demon (don't > | understand why are people so aggressive about that) if you don't need > | up-to-second synchronization (in my case modern hardware goes less than a > | second off per day, and really old hardware - less than 10 seconds). > > The problem here is the jump in time. You repeat a second or more (if > you have to jump back) or skip some (if you jump forward). This may > not be a problem for you in particular, but is considered bad in > general.
rdate can use adjtime, so that point is moot. > Another issue is the fact that the server you're syncing to may not be > perfectly sync'ed itself. Or maybe there's some (assymmetrical) delay > in the network. This may make time on your machine somewhat off (this > isn't as big a problem as the previous, IMO). this is the key. rdate sets/skews the clock based on a single reply. which might get affected badly by network issues or whatever, or be spoofed, or... ntpd doesn't have that problem at all - last not least it never uses less than 8 packets to form a single update (just picking that one as example, there is more it can do, because it can develop thing over TIME instead of a single one-shot update & exit. and it fixes the clock frequency permanently using adjtick. rdate doesn't. > And it's totally unneccessary, simply run ntpd and be done > with it. exactly. -- Henning Brauer, [EMAIL PROTECTED], [EMAIL PROTECTED] BS Web Services, http://bsws.de Full-Service ISP - Secure Hosting, Mail and DNS Services Dedicated Servers, Rootservers, Application Hosting - Hamburg & Amsterdam
