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March 10, 2014

Getting 3000 clocks up to speed, always

ClockgoingforwardThe US rolled its clocks forward by one hour this past weekend. There are usually  questions in this season about keeping 3000 clocks in sync, for anyone who hasn't figured this out over the last several years. US law has altered our clock-changing weekends during that time, but the process to do so is proven.

Donna Hofmeister, whose firm Allegro Consultants hosts the free nettime utility, explains how time checks on a regular basis keep your clocks, well, regular.

This past Sunday, when using SETCLOCK to set the time ahead one hour, should the timezone be advanced one hour as well?

The cure is to run a clock setting job every Sunday and not go running about twice a year. You'll gain the benefit of regular scheduling and a mostly time-sync'd system.

In step a-1 of the job supplied below you'll find the following line:

    !/NTP/CURRENT/bin/ntpdate "-B timesrv.someplace.com"

Clearly, this needs to be changed.

If for some dreadful reason you're not running NTP, you might want to check out 'nettime'. And while you're there, pick up a copy of 'bigdirs' and run it -- please!

Also, this job depends on the variable TZ being set -- which is easily done in your system logon udc:


Adapt as needed. And don't forget -- if your tztab file is out of date, just grab a copy from another system. It's just a file.

This job below was adapted from logic developed by Paul Christidis:

!# from the help text for setclock....
!# Results of the Time Zone Form
!#   If the change in time zone is to a later time (a change to Daylight
!#   Savings Time or an "Eastern" geographic movement), both local time
!#   and the time zone offset are changed immediately.
!#   The effect is that users of local system time will see an immediate
!#   jump forward to the new time zone, while users of Universal Time
!#   will see no change.
!#   If the change in time zone is to an earlier time (a change from
!#   Daylight Savings to Standard Time or a "Western" geographic
!#   movement), the time zone offset is changed immediately.  Then the
!#   local time slows down until the system time corresponds to the
!#   time in the new time zone.
!#   The effect is that users of local system time will see a gradual
!#   slowdown to match the new time zone, while users of Universal Time
!#   will see an immediate forward jump, then a slowdown until the
!#   system time again matches "real" Universal Time.
!#   This method of changing time zones ensures that no out-of-sequence
!#   time stamps will occur either in local time or in Universal Time.
!showjob job=@j
!TELLOP =====================================  SETTIME   A-1
!/NTP/CURRENT/bin/ntpdate "-B timesrv.someplace.com"
!if hpcierr <> 0
!  echo hpcierr !hpcierr (!hpcierrmsg)
!  showvar
!  tellop NTPDATE problem
!tellop SETTIME -- Pausing for time adjustment to complete....
!pause 60
!TELLOP =====================================  SETTIME   B-1
!setvar FallPoint &
!   (hpyyyy<=2006 AND (hpmonth = 10 AND hpdate > 24)) OR &
!   (hpyyyy>=2007 AND (hpmonth = 11 AND hpdate < 8))
!setvar SpringPoint &
!   (hpyyyy<=2006 AND (hpmonth =  4 AND hpdate< 8)) OR &
!   (hpyyyy>=2007 AND (hpmonth =  3 AND (hpdate > 7 AND hpdate < 15)))
!# TZ should always be found
! if hpday = 1
!    if SpringPoint
!# switch to daylight savings time
!      setvar _tz_offset   ![rht(lft(TZ,4),1)]-1
!      setclock timezone=w![_tz_offset]:00
!    elseif FallPoint
!# switch to standard time
!      setvar _tz_offset   ![rht(lft(TZ,4),1)]
!      setclock timezone=w![_tz_offset]:00
!    endif
!  endif
!TELLOP =====================================  SETTIME   C-1

Mark Ranft of 3k Pro added some experience with international clocks on the 3000.

If international time conversion is important to you, there are two additional things to do.

1) Set a system-wide UDC to set the TZ variable. (And perhaps account UDCs if accounts are for different locations)

:showvar tz

2) There is also a tztab.lib.sys that needs to be updated when countries change when or if they do DST.

:l tztab.lib.sys
ACCOUNT=  SYS         GROUP=  LIB     

FILENAME  CODE  ------------LOGICAL RECORD-----------  ----SPACE----
                 SIZE  TYP        EOF      LIMIT R/B  SECTORS #X MX

TZTAB            1276B  VA         681        681   1       96  1  8

:print tztab.lib
# @(#) HP C/iX Library A.75.03  2008-02-26

# Mitteleuropaeische Zeit, Mitteleuropaeische Sommerzeit
0 3 25-31 3  1983-2038 0   MESZ-2
0 2 24-30 9  1983-1995 0   MEZ-1
0 2 25-31 10 1996-2038 0   MEZ-1

# Middle European Time, Middle European Time Daylight Savings Time 
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10:17 PM in Hidden Value, Homesteading | Permalink

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