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