Simple RPG Subfile Program

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March 22, 2025

OK folks, it’s time to look at a simple RPG sub file program.

And when I say simple, I mean really simple. I’m gonna write a piece of RPG code, keeping the subfile as clean and basic as possible. Really focused on old AS400 style RPG. This is how I started on the System 38, back in the day, and RPG code looked like this and felt like this. For me as a young noob programmer (with significantly darker hair and a significantly trimmer waistline) the mysterious art of writing an RPG subfile program was the pinnacle to which all young programmers tried to climb.

So come with me while I record A short video and talk you through the display file and how this works in the world of sub files:

Right, that all made sense. Didn’t it?

Good, I’m glad you are now the master of the DDS display file because now it’s time to dive into the RPG.

So, let’s have a look at the RPG code based on old AS400 column based RPG. This is old, but you’ll still see this in the wild, so it’s worth covering this for all beginners:

That’s enough blathering from me for a while…

Now it’s time record the next couple of videos converting this old AS400 RPG to free format iSERIES style and then to fully modern IBM i RPG ILE code style.

Oh what fun!

NickLitten


IBM i Software Developer, Digital Dad, AS400 Anarchist, RPG Modernizer, Shameless Trekkie, Belligerent Nerd, Englishman Abroad and Passionate Eater of Cheese and Biscuits.

Nick Litten Dot Com is a mixture of blog posts that can be sometimes serious, frequently playful and probably down-right pointless all in the space of a day.

Enjoy your stay, feel free to comment and remember: If at first you don't succeed then skydiving probably isn't a hobby you should look into.

Nick Litten

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