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ntp 4.2.6p5

    1: HP e3000 MPE/iX NTP Hints - May 29, 2001
    2: ----------------------------------------
    3: 
    4: NTP was first ported to MPE several years ago, but those diffs were never
    5: submitted back to the official NTP distribution.  For more information about
    6: that deprecated port, please see http://www.bixby.org/mark/xntpix.html.
    7: 
    8: NTP was re-ported to MPE in May 2001.  What follows are hints learned from
    9: working with NTP 4.0.99k23.  For additional information about NTP on MPE,
   10: please see http://jazz.external.hp.com/src/hp_freeware/ntp/.
   11: 
   12: MPE lacks the clock-related APIs expected by NTP, so adjtime(), gettimeofday(),
   13: and settimeofday() all had to be implemented from scratch by calling
   14: privileged, undocumented internal OS functions.
   15: 
   16: Unfortunately the implementation of adjtime() has exposed a sub-second accuracy
   17: bug when slewing the system time.  This bug is documented in SR 5003462838, and
   18: exists on all current versions of MPE.  It has not been fixed at the time of
   19: this writing.  The adjtime() code may possibly need to be altered if/when this
   20: bug is fixed.
   21: 
   22: This bug has a side-effect whereby the ntpd daemon will screw up the hardware
   23: PDC clock time by many minutes if used for continuous clock adjustments or in
   24: the one-time -q mode.  But note that you can safely run ntpd in order to become
   25: a time server if you include "disable ntp" in the ntp.conf configuration file.
   26: 
   27: The one-time clock adjustment functionality of ntpdate and ntp_timeset is not
   28: affected by this bug side-effect.  You can safely use these commands to alter
   29: your system time with reasonable accuracy.
   30: 
   31: The only reference clock that has been tested on MPE is the local clock.  So
   32: building NTP with --disable-all-clocks --enable-LOCAL_CLOCK is strongly
   33: recommended.
   34: 
   35: NTP makes use of Privileged Mode (PM) capability in order to bind to the NTP
   36: network port (123) and to access the low-level clock functions.
   37: 
   38: NTP was ported using the gcc compiler.  Attempting to use the HP C/iX compiler
   39: is not recommended and has not been tested.
   40: 
   41: Please note that NTP is not an HP product and is NOT supported by HP.  The best
   42: place for asking MPE-specific questions about NTP is the HP3000-L mailing list
   43: at http://raven.utc.edu/Archives/hp3000-l.html or the associated Usenet
   44: newsgroup of comp.sys.hp.mpe.
   45: 
   46: The original author of this port is:
   47: 
   48: Mark Bixby
   49: HP CSY MPE Internet & Interoperability Engineer
   50: mark_bixby@hp.com