Books on this subject:
RPG IV Jump Start : Moving Ahead With the New RPG
Programming in RPG IV
RPG IV By Example

Just take a look at all the limitations that have disappeared, think about the easier coding for string and arithmetic expressions and the choice should be clear. Whether or not you'll be using the ILE capabilities (service programs, modules, ...) is another question, but I would at least start with RPG IV (or whatever it might be called) and use the CRTBNDRPG option. So far I haven't encountered any disadvantage except that compilation times (including the CRTPGM) are a bit longer compared to before.

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Take your migration in two steps.

1) Focus on the Language (i.e. RPG-IV).

The features such as date/time arithmetic and many more are more than worth the effort which is relatively minor. As Paul indicated, the freedom from limits is worth the move all by itself.

2) Learn the ILE piece (they are separate - one does not require the other) separately. ILE tends to be difficult for many AS/400 people. If you have any old mainframe folks in your shop, they'll tell you that IBM finally brought the linkage editor to the 400. Approcah ILE with caution using modular programming only where necessary and major benefit can be gained. In most cases we've found that the complexity of modular programming isn't worth the gain, but RPG-IV is.

We converted all of our old RPG/400 (actually RPG-III and some RPG-II code) to RPG-IV via the converter that IBM provided without incident one weekend. All of our 5,000 plus programs compiled and ran without incident. They did a real good job on the converter, just create new source files with the proper record lenght, set up a CL and let her rip.

You may want to check NEWS/400's or Midrange Computing's list of books and buy some of. I can't remember the title, but there is on book (small green book) that explains the differences and introduces the new op codes to an experienced RPG-III programmer. That was all we needed to get the migration done. We did conduct a seminar where we used overhead foils to present the new features to the programmers and spend 1/2 day talking about them (including ILE). We did no other training.

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There is another "problem", the compiled objects are about double size than RPG400 programs.

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I have a shareware tool that might help you out too. It is call Convert ILE Format (CVTILEFMT). It is run after you convert the source from RPG to RPG/IV using IBMs CVTRPGSRC command. It formats the source into a free-format style. It is very similar to Connection 2000's convert program (but doesn't cost anything). You can view examples and download the program at my web site: http://www.bvstools.com Feel free to ask questions, etc.

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