--- doc/build/Attic/loncapatimesync.html 2001/02/07 13:10:16 1.1 +++ doc/build/Attic/loncapatimesync.html 2001/09/07 14:54:47 1.2 @@ -24,5 +24,68 @@ the time of the server be kept accuratel

Accuracy involves

- - +
+I will explain the components of ntp and how they
+interrelate on a LON-CAPA system
+
+There are three relevant components here:
+1. a correct /etc/ntp/step-tickers,
+2. a correct /etc/ntp.conf
+3. enabling xntpd for boot up
+
+Without /etc/ntp.conf, /etc/rc.d/init.d/xntpd won't do anything.
+With /etc/ntp.conf but without /etc/ntp/step-tickers, Gerd is correct
+when he says:
+
+> What I do know is that if the clock in the CMOS is off by too much,the normal
+> ntp will not work. Instead, the clock has to be forced to synch initially,and
+> from then on can be automatically adjusted.
+
+The unix commands for Gerd's manual approach are:
+/etc/rc.d/init.d/xntpd stop
+/usr/sbin/ntpdate ntp.msu.edu (or whatever your ntp server is)
+/etc/rc.d/init.d/xntpd start
+
+To force xntpd to avoid the offset problem, defining
+/etc/ntp/step-tickers does the trick.
+
+With /etc/ntp.conf and /etc/ntp/step-tickers, xntp still may not
+work (depending on whether the last instruction was followed
+for the LON-CAPA installation, see
+http://install.lon-capa.org/docs/3.1/instructions_with_cd.html)
+
+Making sure xntp starts up upon boot time should simply
+be a matter of:
+
+/sbin/chkconfig xntpd on
+
+Finally, the correct settings for /etc/ntp.conf
+and /etc/ntp/step-tickers are:
+
+1 line with the ip address of your ntp server
+
+For instance:
+
+echo "whistler.sfu.ca" > /etc/ntp/step-tickers
+echo "whistler.sfu.ca" > /etc/ntp.conf
+
+Everyone is currently setting these and other LON-CAPA conf
+files manually after cvs upgrades, because
+there were several parties who were
+
+* doing different things
+* in different ways
+* for different reasons
+* for different institutions
+* for their machine-specific configurations
+
+I was not able to make everyone happy with
+"make configinstall".  For the future, we (Guy and I) do think
+we've come up with a new way to do everything
+for everyone for updating configuration files
+as the CVS source repository changes.
+
+-Scott
+
+ +