release_notes

IEEE 1588-2002编程源码

RELEASE_NOTES for PTPd


v1a1, 25 May 2005:

This is the first public source code release of PTPd. The source has been
compiled with gcc and tested on an x86 Linux machine. The code may work on
big-endian machines as well, but it will only work on 32-bit Linux machines.

This release also includes a kernel module that generates a pulse-per-second
(PPS) on the most significant data bit of a PC parallel port. The PPS
generated by PTP systems can be used to verify their clock coordination. The
included PPS generator is not precise, so it does not provide a good way to
quantify the time coordination precision.

All of this code is a work in progress. Please feel free to mess around with
it and use it as you wish. While I can offer no support, I welcome any
questions/comments on porting, bugs, features, or anything else. One
exception, please do not ask me what PTP is. One can learn more about PTP
from the IEEE 1588 specification, and one can join the LXI Consortium to
work with the companies using PTP.

Finally, this release is not intended to be a functional PTP system
(although one can be built from it using 'gcc ptpd.c -o ptpd'). It should
not be too hard to figure out how to use it if you dig into the source.

   -kendall


v1a2, 4 June 2005:

PTPd can now be built with 'make'. It also includes a little bit of usage
information in README. This release also fixes a broken clock servo that
caused a slave with a time greater than master clock time to run away from
master clock time. Finally, it includes an updated 'parpp' that hopefully
can be used to precisely quantify the precision of clock coordination.

   -kendall


v1a3, 17 August 2005:

Lots of changes. PTPd functions essentially the same as before, but the code has
been reorganized and trimmed. Also, PTPd now has a real clock servo, and there
is a hook for kernel send time stamps. The stock Linux kernel does not have
a send time stamp, so you'll have to implement your own. I'd be glad to provide
instructions how or kernel patches if anyone is interested. PTPd has shown the
ability to hold coordination solidly within 10us running on a 66MHz M68k.

   -kendall


v1a4, 24 September 2005:

A fair amount of changes, most of which I do not recall. Fixing support for all
of the management messages is one that comes to mind. A fix that sets socket
reuse is another one. Also, there's a fix to the initial clock reset that
allows it to start up very close to master clock time. In general, this release
is more stream-lining and tightening up core functionality. I think that the
protocol stack and the clock servo are feature complete for v1. I will be
testing this release at the IEEE 1588 conference in Zurich. After that, I will
probably tag my next release as beta.

   -kendall


v1b1, 18 October 2005:

The site seems to be getting some downloads, so I want this latest code out
there. There are only small changes. The number of foreign master records now
has a command-line option. Also, the the 'Q' randomization of Delay Request
messages is essentially disabled because I realized it was not implemented
correctly. This is no big deal, because PTPd's Delay Requests do not occur in a
consistent part of the Sync interval window, so they are implicitly randomized.
Anyway, PTPd has been plug-fested a couple of times, and everything seems to
work well, so I am comfortable calling this a beta release. Hopefully people
will try the program out and help shake out some bugs.

   -kendall


v1b2, 8 December 2005:

There has been no feedback from the previous release, so this release does not
contain any significant changes to the source. This release is just the few
minor source changes still sitting in CVS, along with some cleaning of the extra
bits like the documentation and tools. Also, I have removed the 'parpp' tool
from the distribution because its use is not straightforward, and I think it may
be more confusing than helpful to casual users. Finally, I included a PDF of the
paper I wrote for the 2005 Conference on IEEE 1588 to make up for my languishing
source code documentation effort.

   -kendall


v1b3, 6 March 2006:

There has been some useful feedback since the last release. This release
contains some requested bug fixes including an update of the default UTC offset.
This release also adds a requested slave-only mode. Thanks to everyone for the
input.

   -kendall