The language of the AS/400

What is it?

Report Program Generator (RPG) is the programming language traditionally associated with IBM's best-selling mid-range system, the AS/400. Over the past year, IBM has been bringing AS/400 into line with its other servers. AS/400 developers in future will use Java, XML and Websphere. The move will take time, however. The majority of AS/400 business applications are written in RPG, tightly integrated with DB2 UDB/400. Most of those that are not are in Cobol or C/C++.

What is it for?

RPG was built for heavyweight business applications. It was also designed from the outset to co-exist with other programming languages. IBM's plan is to e-business-enable existing RPG applications without touching the core code, so that they can be extended using more modern tools.

Where did it originate?

With the System/3x range (the S/34, S/36 and S/38) of small to medium size business systems. The System/3x range was replaced by the AS (Application System)/400 in June 1988.

What makes it special?

While the majority of RPG applications are still written to the original program model, an increasing number are moving to the Integrated Language Environment (ILE). ILE supports a number of programming technologies, including RPG, Cobol and C/C++.

Extensions to ILE RPG will improve integration between runtime environments and provide direct access to applications, such as Java programs, running in other AS/400 environments.

How difficult is it?

IBM has been adding tools such as the Program Call Mark-up Language (PCML) toolset, which includes a GUI builder. PCML insulates the application from changes in client GUI technology.

Where is it used?

Nine of the 10 leading ERP packages, including SAP, Baan, JD Edwards, Peoplesoft and SSA, run on the AS/400. There are still many AS/400-only shops that rigidly adhere to the green-screen environment, and a smaller but growing community that uses AS/400 for e-commerce.

Not to be confused with

MPG (miles per gallon), LPG (liquid petroleum gas), rocket propelled grenades.

What does it run on?

RPG/400 runs on AS/400. Earlier versions of RPG run on surviving S/3x models, which some people simply refuse to give up.

Few can understand

IBM's new server names. AS/400 is now the e-server iSeries and the mainframe the zSeries. Perhaps it should call the whole lot the y?Series.

What's coming up?

In future, all graphical, compiler, text-based and Web-facing tools for the AS/400 will be delivered as a single integrated package. Websphere Development Tools is an open, standards-based product that supports all the languages available on AS/400, using the Application Development Tool Set (ADTS), ILE RPG, ILE Cobol and ILE C/C++.

Rates of pay

RPG/400 has slipped out of the Computer Weekly/SSP top 25 skills. The end of Y2K, mergers and acquisitions, and logical partitioning - which consolidates many AS/400s into one - have helped reduce the need for AS/400-qualified staff.

Programmer: £25,514

Analyst programmer: £28,333

Senior analyst programmer: £34,708

Source: CW/SSP Salary Survey