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diff --git a/usr.sbin/xntpd/parse/README b/usr.sbin/xntpd/parse/README deleted file mode 100644 index aa83aa7..0000000 --- a/usr.sbin/xntpd/parse/README +++ /dev/null @@ -1,100 +0,0 @@ -PARSE reference clock driver: - -This directory contains the files making up the parser for -the parse refclock driver. For reasonably sane clocks this refclock -drivers allows a refclock implementation by just providing a -conversion routine and the appropriate NTP parameters. Refclock -support can run as low a 3k code with the parse refclock driver. - -The modules in here are designed to live in two worlds. In userlevel -as part of the xntp daemon and in kernel land as part of a STREAMS module -or, if someone gets to it, as part of a line discipline. Currently only -SunOS4.x/SunOS5.x STREAMS are supported (volunteers for other vendors like HP?). -This structure means, that refclock_parse can work with or without kernel -support. Kernelsupport increases accuracy tremendingly. The current restriction -of the parse driver is that it only supports SYSV type ttys and that kernel -support is only available for Suns right now. - -Three kernel modules are part of this directory. These work only on -SunOS (SunOS4 and SunOS5 (not fully tested!)). - - SunOS4 (aka Solaris 1.x): - parsestreams.o - standard parse module for SunOS 4 - mparsestreams.o - parse module for SunOS 4 with better - clock reading code (assembler) - - Both modules can be loaded via modload <modulename>. - - SunOS5 (aka Solaris 2.x): - parse - auto loadable streams module - (not fully tested - don't kill me if - it kills you machine) - - To install just drop "parse" into /kernel/strmod and - start the daemon (SunOS5 will do the rest). - -The structure of the parse reference clock driver is as follows: - - xntpd - contains NTP implementation and calls a reference clock - 127.127.8.x which is implemented by - refclock_parse.c - - which contains several refclock decriptions. These are - selected by the x part of the refclock address. - The lower two bits specify the device to use. Thus the - value (x % 4) determines the device to open - (/dev/refclock-0 - /dev/refclock-3). - - The kind of clock is selected by bits 2-6. This parameter - selects the clock type which deterimines how I/O is done, - the tty parameters and the NTP parameters. - - refclock_parse operates on an abstract reference clock - that delivers time stamps and stati. Offsets and sychron- - isation information is derived from this data and passed - on to refclock_receive of xntp which uses that data for - syncronisation. - - The abstract reference clock is generated by the parse* - routines. They parse the incoming data stream from the - clock and convert it to the appropriate time stamps. - The data is also mapped int the abstract clock states - POWERUP - clock has no valid phase and time code - information - - NOSYNC - Time code is not confirmed, phase is probably - ok. - SYNC - Time code and phase are correct. - - A clock is trusted for a certain time (type parameter) when - it leaves the SYNC state. This is derived from the - observation that quite a few clocks can still generate good - time code information when losing contact to their - synchronisation source. When the clock does not reagain - synchronisation in that trust period it will be deemed - unsynchronised until it regains synchronisation. The same - will happen if xntp sees the clock unsynchronised at - startup. - - The upper bit of x specifies that all samples delivered - from the clock should be used to discipline the NTP - loppfilter. For clock with accurate once a second time - information this means big improvements for time keeping. - A prerequisite for passing on the time stamps to - the loopfilter is, that the clock is in synchronised state. - - parse.c These are the general routines to parse the incoming data - stream. Usually these routines should not require - modification. - - clk_*.c These files hole the conversion code for the time stamps - and the description how the time code can be parsed and - where the time stamps are to be taken. - If you want to add a new clock type this is the file - you need to write in addition to mention it in - parse_conf.c and setting up the NTP and TTY parameters - in refclock_parse.c. - -Further information can be found in parse/README.parse and the various source -files. - -Frank Kardel |
