/contrib/ntp/html/build/hints/mpeix

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