This ILE business isn't simple. I know a lot of bright people who have had real problems moving across from RPGIII to RPGIV and ILE. So you can imagine the problems that not-so-bright people like me have had.

It's not the RPGIV part that's the problem, on the whole. RPGIV is just RPGIII dragged kicking and screaming into the nineteen-eighties. The thing that people have real problems with is ILE.

You can find a lot of good stuff in Who Knew You Could Do That with RPG IV? A Sorcerer's Guide. The first four chapters are essential reading for RPG programmers.

Adding Subprocedures to a Service Program is a nice little tutorial on binder language. You can use this to avoid the need for mass recompilation when you change a service program. It's knowing things like this which mean the difference between ILE being useful and being a complete nightmare.

Update (Frday) 13th of July: Reader Feedback and Insights: Binder Language clears up a few bits and bobs.