Show MPE how to change the times

In North America, the clocks fall back early Sunday morning. At 2 AM local time you’ll lose an hour in the misguided but official Daylight Saving Time scheme. Note, not Savings. But there’s a lot that’s broken about the concept of shifting an hour back and forth in March and November.

We’re saving energy by doing this. The US government made this change a law in the 1970s, when OPEC threatened energy costs. A few things, like shale oil deposits and fracking, have changed energy since then.

However, there’s still this time change to account for in the OS of your HP 3000. That’s true whether it’s a virtual system like the ones in Charon sites, or an actual box of metal assembled and wired up by HP. At least 18 years ago, that box was built. Congratulations on keeping the old iron running.

To the surprise of nobody, HP didn’t create an automatic time change function for MPE. Instead, sharp administrators and managers run a jobstream every year in the fall and the spring. John Burke managed 3000s for many years. He takes it from here.

Set your clock with SETCLOCK

My nominee for the most commonly used, yet least well understood, feature of MPE/iX: the system clock and the SETCLOCK command. In the US, most of us use this command at least twice a year: when we switch to Daylight Saving Time and when we switch back to Standard time. Even if SHOWTIME seems to give the correct time, there is a very good chance your system has an incorrect value for Timezone and/or GMT.

You must set it up correctly yourself when you configure a new machine. You use the timezone form of the SETCLOCK command. Here is a snippet of JCL from a scheduled job stream I use that runs at 2:00 a.m. Sundays (I am located in the Pacific timezone of the US, so adjust as necessary):

!IF HPDAY = 1 AND HPMONTH = 10 AND HPDATE > 24 THEN
! SETCLOCK TIMEZONE = W8:00
!ELSEIF HPDAY = 1 AND HPMONTH = 4 AND HPDATE < 8 THEN
! SETCLOCK TIMEZONE = W7:00
!ENDIF

Leave a Reply