Path: utzoo!attcan!uunet!decwrl!ucbvax!CS.CMU.EDU!Ravinder.Chandhok From: Ravinder.Chandhok@CS.CMU.EDU (Rob Chandhok) Newsgroups: comp.protocols.appletalk Subject: Re: NTP on the Mac Message-ID: <24518.655741845@GNOME.CS.CMU.EDU> Date: 12 Oct 90 14:30:45 GMT References: <1990Oct11.235244.6595@ux1.cso.uiuc.edu> Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 34 >From: Pete Resnick >Subject: Re: NTP on the Mac > >>Regarding the statement (from Pete Resnick?) that "the math is too hard for >>ntp", if anyone would like to implement a better form of ntp for the mac >>(cdev or init) then please take my sources! John Pane and I figured out how >>to convert from Mac time to ntp's notion of time. The rest of it is just >>getting and sending packets. > >Let me re-phrase: I took a look at the NTP RFC. The math is very complex >and requires repeated packet sends and re-adjustment. My figuring was >that I would not want to bog down my poor little SE with so many >calculations and IP transmissions to set my clock when I don't need the >200 picosecond precision. Anywhere between 2 and 10 second precision >was fine with me, so I used the UDP Time RFC. Wasting more than a couple >of ticks just to get my clock set "reasonably" seemed absurd. Let me re-phrase: the code that I ported to the mac already does all the packet sending & re-adjustment. It is not the ntp demon, so in about 5 seconds you could have an accurate time setting. IT seems to me that if you are going to bother setting the clock, that 2-10 seconds drift is a little loose. If you are going to rely on the time for using file servers, or other reasons for having a correctly synched clock, why not get it right? People waste more ticks with background screens... Oh well. It isn't really that big a deal, unless you really care abou thte time. We use the ntptime tool to ensure our timestamps are good on our projector files. Rob