Although I have been using various versions of Microsoft Windows since the early 1990s, I am still not impressed when I gaze upon that phenomenon popularly known as the “Blue Screen of Death.” In the same way, I do not think iSeries users are impressed when they see the Display Program Messages panel, or as I call it, the “Green Screen of Death.” Fortunately, showing users the Display Program Messages panel is almost always avoidable.

When a program encounters an error that it has not been told how to handle, it stops. For interactive jobs, the user is presented with

I am trying to change part of a character field with an SQL UPDATE command. However, my SQL command gives me an invalid token error at the opening parenthesis of SUBSTR in the SET statement. Is there a rule that you can’t use SUBSTR in a SET statement? If so, do you have a workaround?

–Dennis

What you’re trying to do is reasonable, Dennis. After all, RPG and CL let you change part of a character field using their %SUBST and %SST functions. But SQL is different.

For the benefit of other readers, here is the SQL command Dennis sent

Like all computers, i5, iSeries, and AS/400 systems are vulnerable to system failures when their disk storage units fill up. i5/OS operating system performance rapidly degrades after system storage reaches 90 percent capacity, and the system can crash–or turn itself off–when storage passes 95 percent. Because of this, it’s wise to understand how your system handles critical storage situations and how it can alert you when disk capacity problems appear.

Critical storage situations can occur anytime system storage approaches and passes 90 percent, and several common situations can put you over the limit. A runaway job can fill up disk