xref: /freebsd-9.3-release/contrib/ntp/html/hints/a-ux

-------------
INTRODUCTION:
-------------
Last revision:  06-Jul-1994

Included in this distribution of XNTP V3 is a configuration file suitable
for use under Apple's A/UX Version 3.x.x  There is also one for A/UX 2.0.1
but it has not been fully tested. To make the executables follow the steps
outlined below.

*** NOTE:  You must have gcc installed to successfully compile the current
distribution; the native cc supplied with A/UX will NOT correctly compile
this source.  See the FAQ in comp.unix.aux for places to obtain gcc from
and how to install it.

----------------------
MAKING XNTPD FOR A/UX:
----------------------

First, you need to create the makefiles (after you've downloaded the
source, of course):

    % make clean
    % make refconf

After that, you should edit Config.local to make sure that BINDIR is
correct for where you wish the programs to be "installed". The default
(and what I use) is /usr/local/etc. Make sure that DEFS_LOCAL and
CLOCKDEFS are commented out! Presently, only the LOCAL_CLOCK/REFCLOCK
clock is used and supported.


After this is done (you should be told that your system is A/UX 3), make
'xntpd' (the options to 'gcc' are held in compilers/aux3.gcc):

    % make

I do not normally use the `make install' option and so have not verified its
compatibility with A/UX.  Rather, I pull out each of the executables and
place them in the locally appropriate locations.

---------------
STARTING XNTPD:
---------------

At this point you need to set things up so that 'xntpd' is started upon
boot-up. You can do this in 1 of 2 ways: either add entries in /etc/inittab
or, more ideally, create and use an /etc/rc.local file. Since rc.local is
what I recommend, here's how you do it:

By default, A/UX doesn't have rc.local, so you'll need to add the following to
/etc/inittab:

    net6:2:wait:/etc/syslogd		# set to "wait" to run a syslog daemon
+   jmj0:2:wait:/etc/rc.local 1>/dev/syscon 2>&1	# Local stuff
    dbg2::wait:/etc/telinit v	# turn off init's verbose mode

Now, the look of a sample /etc/rc.local is as follows:

    #!/bin/sh
    :
    : rc.local
    :
    #	@(#)Copyright Apple Computer 1987	Version 1.17 of rc.sh on 91/11/08 15:56:21 (ATT 1.12)
    
    
    #	Push line discipline/set the device so it will print
    /etc/line_sane 1
    echo " "
    echo "Entering rc.local..."
    
    set `/bin/who -r`
    if [ "$7" = 2 ]
    then
        /bin/echo " now setting the time..."
        /usr/local/etc/ntpdate -s -b <host.domain>
        sleep 5
    #
    # start up 'xntpd' if we want
    #
        if [ -f /etc/ntp.conf ]
        then
    	/bin/echo " setting tick and tickadj..."
    	/usr/local/etc/tickadj -t 16672 -a 54
    	sleep 5
    	/bin/echo " starting xntpd..."
    	/usr/local/etc/xntpd <&- > /dev/null 2>&1
    	sleep 5
        fi
    #
    fi
    
    echo "Leaving rc.local..."

There are a few things to notice about the above:

    o When run, 'ntpdate' forces your clock to the time returned by the
      host(s) specified by <host.domain> (you'll need to replace this
      be the IP address(es) of your timehosts. This is good since it gets
      things close to start off with. You can use more than one time
      server.

    o 'tickadj' is also called. This does two things: changes the
      default value of 'tick' (which the the amount of time, in ms, that
      is added to the clock every 1/60 seconds) and changes the value
      of 'tickadj' which the the amount that is added or subtracted
      from 'tickadj' when adjtime() is called.

      Now Mac clocks are pretty bad and tend to be slow. Sooo, instead of
      having A/UX add the default of 16666ms every 1/60th of a second, you
      may want it to add more (or less) so that it keeps better time. The
      above value works for me but your "best" value may be different and
      will likely require some fooling around to find the best value. As a
      general rule of thumb, if you see 'xntpd' make a lot of negative clock
      adjustments, then your clock is fast and you'll need to _decrease_
      the value of 'tick'. If your adjustments are positive, then you need
      to increase 'tick'. To make a guess on how fast/slow your clock is,
      use 'ntpdate' to sync your clock. Now watch 'xntpd' and see how it
      operates. If, for example, it resets your clock by 1 second every 30
      minutes, then your clock is (1/(30*60)) is about 0.056% off and you'll
      need to adjust 'tick' by 16666*0.00056 or about 9 (i.e. 'tick' should
      be ~16675 if slow or ~16657 if fast)

      A/UX's default value of 'tickadj' is 1666 which is too big for
      'xntpd'... so it also needs to be adjusted. I like using larger
      values then the recommended value of 9 for 'tickadj' (although not
      anything near as big as 1666) since this allows for quick slews
      when adjusting the clock. Even with semi-large values of 'tickadj'
      (~200), getting 5ms (1/200 s) accuracy is easy.


Finally, before A/UX and 'xntpd' will work happily together, you need to
patch the kernel. This is due to the fact that A/UX attempts to keep the
UNIX-software clock and the Mac-hardware clock in sync. Neither the h/w or
the s/w clock are too accurate. Also, 'xntpd' will be attempting to adjust
the software clock as well, so having A/UX muck around with it is asking
for headaches. What you therefore need to do is tell the kernel _not_ to
sync the s/w clock with the h/w one. This is done using 'adb'. The
following is a shell script that will do the patch for you:

    #! /bin/sh
    adb -w /unix <<!
    init_time_fix_timeout?4i
    init_time_fix_timeout?w 0x4e75
    init_time_fix_timeout?4i
    $q
    !

This must be done _every_ time you create a new kernel (via newconfig or
newunix) or else 'xntpd' will go crazy.

--------
HISTORY:
--------

John Dundas was the original porter of 'xntpd' and a lot of the additions
and A/UX-ports are from him. I got involved when I wanted to run 'xntpd'
on jagubox. It was also around this time that the base-patchlevel of
'xntpd' changed relatively (the so-called "jones" version). Since then,
I've been maintaining 'xntpd' for A/UX for the xntp development team

The original kernel patch (which patched 'time_fix_timeout') was from
Richard Todd. I suggest patching 'init_time_fix_timeout' which prevents
'time_fix_timeout' from even being called.

----------------
TECHNICAL NOTES:
----------------

    o As configured (see machines/aux3), 'xntpd' will log messages via syslogd
      using the LOC_LOCAL1 facility. I would suggest the following in
      /etc/syslog.conf:

	local1.notice		/usr/adm/ntpd-syslog

    o As mentioned above, the clocks on A/UX and Macs are kinda bad. Not
      only that, but logging in and out of the MacOS mode as well as
      extensive floppy use causes A/UX to drop and lose clock interupts
      (these are sent every 1/60th of a second). So, if you do these
      activities a lot, you find out that you lose about 300ms of time
      (i.e., you become 300ms slow). 'xntpd' default way of handling this
      is to called 'settimeofday()' and step the clock to the correct
      time. I prefer having 'xntpd' slew the clock back into line by
      making gradual adjustments to the clock over a coupla minutes
      or so. It's for this reason that SLEWALWAYS is defined in
      include/ntp_machine.h for SYS_AUX3. It's also for this reason than
      I like larger values of 'tickadj'.

Good luck!  If you have problems under A/UX feel free to contact me (e-mail
is preferred).
--
    Jim Jagielski               |  "That is no ordinary rabbit... 'tis the
    jim@jagubox.gsfc.nasa.gov   |   most foul, cruel and bad-tempered
    NASA/GSFC, Code 734.4       |   rodent you ever set eyes on"
    Greenbelt, MD 20771         |                   Tim the Enchanter