readme.3.4

ftam等标准协议服务器和客户端的源代码。

	Danger: don't attempt to run ntpd on a NeXT machine.  It provokes
	a bug in the OS which hangs the machine quite absolutely.

	There is some support for a statrum 1 clock in some code provided by
	Doug Kingston ([e-mail]).  I'm not really sure that its the
	``right'' way to do it; I'd rather have the clock appear just like
	another peer, and have it selected as a reference, just like you'd
	select any other clock.  In fact, by doing it that way with some other
	support, you could even have a seperate process take care of reading
	the clock, and talking to the main process with some UNIX domain
	sockets... Hmm..

12/8/88
	*** THIS IS A TEST RELEASE ***
	Really.  We have tested this code on a VAX platform, but not much of
	anything else.  I would like to hear back about any bugs, but you 
	should not treat this as a 'release' version.

	Very large number of changes and updates.  Files have been reorganized
	with ntpd.c containing intialization and other very UNIX specific code,
	while the new file ntp_proto.c contains the bulk of the NTP code.
	This version of the UNIX NTP daemon was re-written and updated to
	conform with the revised NTP specification.

	For all of the mucking about with tickadj, you can now define 
	SETTICKADJ in the Makefile, and specify the value of tickadj in 
	/etc/ntp.conf.  The ntpd will attempt to update `tickadj' using 
	/dev/kmem.  Yow!

	If possible, ntpd will attempt to discover the value of your kernel's
	`hz' variable, and set the value of `precison' automagically.  If 
	`precision' is specified in /etc/ntp.conf, it will override any 
	automatic selection.

	Only hosts which are configured or mentioned in /etc/ntp.conf on a
	`peer', `server' or `passive' statement are elligable to be
	synchronized to.  This solves the "ganging-up" problem, but is sorta
	ugly.

	The `peer' statement in /etc/ntp.conf works just as before; it sends
	packets with MODE=SYMMETRIC-ACTIVE to the remote host.  The remote host
	might synchronize to you if appropriate.  If reachability is lost,
	polling will continue.

	The new `server' statement in /etc/ntp.conf causes packets of MODE=
	CLIENT to be sent to the specified host.  The remote host will *not*
	synchronize to you under any circumstances.  If reachability is lost,
	polling will continue.

	The new `passive' statement in /etc/ntp.conf causes packets of
	MODE=SYMMETRIC-PASSIVE to be sent to the remote host *when the local
	host is polled*.  If reachability is lost, then polling will cease
	until the remote host begins to the local host again.

	Note conditional compilation define in the makefile for
	VAX_COMPILER_FLT_BUG for old 4.2 and Ultrix 2.0/2.2/3.0 pcc compilers.
	There is a bug in the code generated to convert an unsigned long to a 
	double.  Previously, this code was always present, but it is now 
	#ifdef'd.  The 4.3BSD-tahoe and GNU CC (1.30 and 1.31 at least) are
	known to work correctly.  If you don't know if your compiler 
	performs this conversion correctly, try making and running the
	`ntest' program, and see if test3 passes or not.

	The format of the data sent between ntpd and the ntpdc programs has
	changed yet again.  It is likely to change again before the final
	release of this version.  

7/30/88
	Added and updated manual entries contributed by Glenn Trewitt.
		([e-mail])
7/27/88
	Reorder peer list so configuted hosts are always first.  This
	REALLY helps the faleticker code.

	Changed ntpdc to have a larger RECV socket buffer. This fixes
	the "only see 20 peers" problem. This is a side affect of using
	UDP for the status return.

6/20/88
	Support for hosts with multiple interfaces.  Minor updates to
	the ntpdc program; note that the format of the messages between
	the ntpd and ntpdc programs is different in this version than the
	last.  You should update both ntpd and ntpdc at the same time.

	New file ``ntp_sock.c''.  Tested with Ultrix 2.4 field test, and 
	4.3 BSD tahoe release.  Debug level can be adjusted by sending
	SIGUSR1 to increase and SIGUSR2 to zero the debug level.

5/17/88
	Changed peer structure alloactor to stop allocating a perm
	structure for non-peer relationships. This make the ntpdc
	output a lot more understandable.
	Installed faletick code.
	Installed work around to bug in Ultrix C compiler.
	The compiler has troubles converting unsigned longs to floats.
	This caused a lot of off by 2 second problems.
3/31/88
	The world is ALL different now.  The NTP protocols have had
	some major structural work.  This is the first rev that
	attempts to meet NTP version 1 compliance.  There are a couple
	of loose ends (faltickers code and clock slew rate) that
	are not finished, but should be RSN.  This release is to
	bridge the compatability with the old clock system.

	CHANGES:
	ntpsubs.c had a MAJOR bug in the tstamp routine.  Accuracy
	should be much better now.

	The ntp.conf file is much simpler.  List your precision
	and peers, the rest is automagic.

	The ntp/udp service mapping is now consitent.  No more hard
	coded 123s. 

	The math routines are more robust.  They now handle signed
	conversion of longs and shorts.

	The control structure of ntpd is radically different.  A peer
	relation is NOT setup for clocks at a higher stratum.  This
	reduces table clutter, but you lose the history of those
	requesters.

2/20/88
	Removed the median filter and replaced it with a minimum
	filter.  Experimentation by Dave Mills suggests this is
	a better way to track network clocks.  Changed status field based
	on updated RFC.

12/29/87
	Only believe samples were the round trip delay is positive.
	I recommend HIGHLY that you change tickadj in /sys/conf/param.c
	to equal 1 instead of 40.  This reduces the granularity of
	clock slewing from 4ms/sec to .1ms/sec.  This should suffice
	if your clock is less that 4.3 minutes per month. If this is
	the case get a new clock, increase the value, or live with
	periodic clock jumps due to setimeofday().  The basic problem is
	that adjtime() slews only with "tickadj" granularity.  That's
	argueably broken, but needs kernel mods to fix it.

12/17/87
	Added some of the changes from Greg Fowler and Ken Stone
	of HP labs.  This adds "hpux" compatability.  Ken and Greg
	also tighten up the "bestclock" determination so you
	don't end up tracking yourself. (thanks again)

	The Precision field in now correct, precision is the power
	of 2 indication of internal clock tics.  (ex. 60-HZ = -6)
	This is a constant for the machine and should be set in the
	ntp.conf file.

12/1/87
	Massive cleanup in the daemon code.  There was a BIG problem
	with "bestclock" peer calculation.  A clock of a lower type would
	be tracked if the delay to that clock was lower than the delay
	to the higher precision clock.  The peers listed in the ntp.conf
	files are marked as PERM.  This causes a ntp gram to go to these
	guys regardless of any recv activity. This eliminates the problem
	of a peer being down and not talking ot him when he comes back
	up because the activity indicator went to zero.  Using PERM
	entries creates a fixed overhead, use it with caution.
	There is the beginning of a second order filter that can be used
	to adjust the kernel tick rate.  More on that when it's done.
	The data structures have changed for queries.  Querying old
	clocks will cause problems.  Note - the NTP protocol has NOT
	changed, only the query hack.  The SET_THRESHOLD has been changed
	to be more reasonable with the max slew rate of 4.3BSD.  This
	will be relaxed when the second order stuff is working.

5/29/87

	All of the internal math is now done with doubles.  This removes
a lot of the hair and cost.  On vaxen the double yields 54(5) bits of
accuracy.  The NTP timestamps are 64 bits.  Converting to doubles
will cause the loss of some bits on ost machines.  This is not bad
since most machines don't have clocks that could track even the lower
16 bits of the NTP timestamps.

	NTP makes three choices on changing the local clock.
	1) If the local clock apperars to be off by more than
	WAYTOOBIG (1000.0) seconds, it refuses to do anything
	but fill up you log.
	2) If the local clock is off less than WAYTOOBIG but more
	than SET_THRESHOLD (2.0) a settimeofday will be done.
	3) If the clock is off less than SET_THRESHOLD an adjustime
	is done.

	Ntpd clears out the samples after every clock adjustment.
	This helped to prevent the filter from overshouting based on old
	data.
===========================================================================
Still cooking on the stove are:

	modify adjtime - it won't allow small adjustments.
		I may punt and put in a new adjtime that handles
		the second order stuff.

	making it handle broadcasted time like timed

	man pages

Any suggestions or help are ALWAYS appreciated.

Louis A. Mamakos  ([e-mail])
mike petry ([e-mail])