RPG III is a dialect of the

RPG programming language RPG is a high-level programming language for business applications, introduced in 1959 for the IBM 1401. It is most well known as the primary programming language of IBM's midrange computer product line, including the IBM i operating system. RP ...

that was first announced with the IBM

System/38 The System/38 is a discontinued minicomputer and midrange computer manufactured and sold by IBM. The system was announced in 1978. The System/38 has 48-bit addressing, which was unique for the time, and a novel integrated database system. It w ...

in 1978. An upgraded version,

RPG IV RPG is a high-level programming language for business applications, introduced in 1959 for the IBM 1401. It is most well known as the primary programming language of IBM's midrange computer product line, including the IBM i operating system. RP ...

, was introduced in 1994. In 2001 RPG was again updated to remove a number of column restrictions. RPG continues to be upgraded on a regular basis. The last fixed form restrictions were removed in 2015. Other than sharing some opcodes and terminology, modern RPG IV is visually very different from RPG III.

Overview

Unlike predecessors, RPG III uses external file descriptions, which means that disk files are built and RPG III programs are attached to them at compile time. Some other noteworthy changes from RPG II include: 1. The object cannot be replaced while active. 2. The object in a test library cannot be moved unilaterally into production. It must be compiled in the library associated with the external files (unlike

System Support Program ''System Support Program (SSP)'' was the operating system of the IBM System/34 and System/36 minicomputers. SSP was a command-based operating system released in 1977. ''SSP'' originally contained 60 or so commands that were implemented on the S ...

Control Program Facility Control Program Facility (CPF) is the operating system of the IBM System/38. CPF represented an independendent line of development at IBM Rochester, and was unrelated to the earlier and more widely used System Support Program operating system. CPF ...

libraries contain data files.) 3. Display formats used by RPG III programs also describe the fields displayed and received by the RPG III WORKSTN file. Therefore, these specifications, called DDS, are also external in nature. 4. The display format object used by an RPG III program must be compiled before the RPG III program itself.

References

{{DEFAULTSORT:Ibm Rpg Iii RPG III High-level programming languages