RPG and the AS/400 platform have a long history.

When the System/3 was introduced in the 1970s, RPG was first released , the language evolved and RPG II use of the logic cycle was many programmers first experience of pullng hair out while staring at a green screen. RPG III was released with the System/38, which included the ability to work with a fully integrated database. In 1994, RPG IV was released, with it's ILE abilities. Now referred to as RPGLE the language is evolving with every release of i5/OS (the IBM operating system).

The ILE version of the system i programming language allows you to write each program in a series of modules and compile each one seperately. Of course, each of these mdules can also be written in different languages. Anthing from CL (java, control language

In this little series of articles I'm are going to try and cover most aspects of simple RPGLE programming syntax, module design and procedural principles. Everything from the Logic Cycle through to modularized techniques.

Due to its evolving naure RPG is frequently described as RPG2, RPG3, RPG400 and most recently RPGLE or RPGILE. Confused? Well dont worry, spend a lunchtime reading these articles and it will all hopefully become clear.

We will go through the RPGLE variables, conditional execution, subroutines and the input/process/output routines. After this we can move into the more complex areas of posting data to the AS400 database.

The final objective will be lead you through a simple RPG program taking screen input and veriying and updating an AS400 database.