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