[Info-vax] Time change

[Richard B. Gilbert]

Michael Moroney wrote:
> JF Mezei <jfmezei.spamnot at vaxination.ca> writes:
> 
>> How is this implemented in alpha ? Does the system do a glorified
>> SYS$SETTIM to call a routine to execute at the next scheduled time
>> change ?  or is there some other type of mechanism that allows VMS to
>> schedule some event in the long term ?
> 
>> Also, if I have an alpha that was shutdown during this time, when it
>> next boots, will it automatically change its time ?
> 
> I had to deal with this during the last time change, to try to prevent
> the setback from happening automatically with software that really 
> couldn't deal with it.
> 
> (the following is true only if SYSGEN AUTO_DLIGHT_SAV is set to 1, and
> things like NTP time synch aren't enabled. What's the setting on your
> VAX?)
> 
> The JOB_CONTROL process has a $SETIMR scheduled to expire at the time of
> the time change, and when it does, JOB_CONTROL sets the time according to
> the time zone rules.  It reads the info in when it starts up, and it has
> enough smarts to set the time right then if the time change happened when
> the system was down.
> 
> $ ANALYZE/SYSTEM
> SDA> SET PROCESS/IND=E   !JOB_CONTROL
> SDA> SHOW TQE
> Timer queue entries
> -------------------
> 
>   TQE                                                             PID/
> address                 Expiration Time                 Type    routine
> --------   -----------------------------------------   ------   --------
> ...
> 880EA380   00A93E1F.7B714530  1-NOV-2009 02:00:00.00   TSA---   0001000E   JOB_CONTROL
> SDA>
> 
> Next time change will take place Nov 1 at 2:00 AM.
> 
> 
> 
> You may notice that $SETIMR can schedule events to happen thousands of
> years in the future, if you can manage to keep your system up that long.
> 
> Aside: Were you guys in Canada supposed to change your time this last
> weekend?  The date of the time change was recently changed.

It's politics as usual.  Changing the date of the time change is a 
highly visible means for the politicians to show the people that they 
are actually doing something!  ;-)