IT professionals continue to use the word AS/400 and refer to applications as IBM AS/400 iSeries Cobol, AS/400 iSeries RPG, etc. The word AS/400 is seen in professional titles and certifications. Despite its newer avatars, AS/400 is still being used by enterprises. Introduced way back in 1988, and still in the reckoning now, this hardware platform is as important as its successors. Present-day iSeries consulting is not only about IBM Power Systems, as it’s also about AS/400 support. Let’s go through the blog to understand the modernization challenges and the best solution.

Why is AS/400 a Venerable Server Platform?

AS/400 is A Stable Platform

When IBM introduced the AS/400 with the OS/400, the server platform had a discrete set of core functions, applications written in now what we refer to as iSeries Cobol apps, and an integrated database. Over the years, this hardware and software combination underwent multiple revisions, name changes, and upgrades.

In its contemporary avatar as iSeries platform, AS/400 is part of the IBM Power Systems based on the IBM Power processor and the updated IBM i operating system along with iSeries Cobol, RPG, and other applications developed in popular high-level programming languages.

AS/400 is Forward Compatible

From the beginning, this platform family’s strong point has been its forward compatibility. It means that AS/400 applications built on OS/400 will continue to run without disruption on the iSeries platforms as iSeries Cobol, RPG apps. A program that was created in 1988 for AS/400 will run on Power Systems hardware even today, with little or negligible changes. This is why iSeries consulting firms are required to manage AS/400 infrastructure alongside platform infrastructure.

The forward compatibility is why companies queued up to purchase AS/400. Even after multiple revisions and upgrades, none of the legacy applications were disrupted and continue to run as iSeries Cobol and RPG apps. This aspect prompted companies to look for a stable non-myopic platform.

This is one of the other reasons why companies that use robust systems today still refer to their server infrastructure as AS/400. Because these companies would have upgraded their AS/400 systems to the new iSeries platform and yet there could be several legacy applications running on the new platform as iSeries Cobol or RPG native applications.

Source- https://www.integrativesystems.com/ibmi-modernization/