Editing IBM RPG (section)

===RPG III===
{{main|RPG III}}
''RPG III'' was created for the [[System/38]] and its successor the [[AS/400]].  RPG III significantly departed from the original language, providing modern structured constructs like IF-ENDIF blocks, DO loops, and [[subroutine]]s.  RPG III was also available for larger systems including the [[IBM System/370]] mainframe running [[OS/VS1]]. It was also available from [[Unisys]] for the [[VS/9]] operating system running on the [[UNIVAC Series 90]] mainframes.

Since the introduction of the [[IBM System/38]] in 1979 most RPG programmers discontinued use of the cycle in favor of controlling program flow with standard looping constructs, although IBM has continued to provide backward compatibility for the cycle.

====DE/RPG====
''DE/RPG'' or Data Entry RPG was exclusively available on the [[IBM 5280]] series of data-entry workstations in the early '80s. It was similar to RPG III but lacking external Data Descriptions (DDS) to describe data(files) like on the System/38 and its successors. Instead, the DDS part had to be included into the RPG source itself.

====RPG/400====

''RPG/400'' was effectively RPG III running on AS/400. IBM renamed the RPG compiler as "RPG/400" but at the time of its introduction it was identical to the RPG III compiler on System/38. Virtually all IBM System/38 products were rebranded as xxx/400 and the RPG compiler was no exception. RPG III compiled with the RPG/400 compiler offered nothing new to the RPG III language until IBM began development of new operation codes, such as SCAN, CAT and XLATE after several years of AS/400 availability. These enhancements to RPG III were not available in the System/38 version of RPG III.