Why RPG Modernization with Thinkwise Is the Most Efficient Path Forward

A field report based on 35+ years of IBM i project experience
Guest article by Jürgen Schmidt, rsb-Schulung – Thinkwise Partner

For more than three decades, I’ve supported companies running on IBM i (formerly AS/400) — a platform known for its stability and longevity. Throughout these years, I’ve seen many of these organizations struggle to bring their proven RPG applications into the modern IT landscape.

The reasons are well known: decades-old code, missing documentation, and the dwindling availability of experienced RPG developers. At the same time, these applications remain business-critical, forming the backbone of countless production, logistics, and ERP systems.

Throughout numerous modernization projects, I’ve encountered every possible approach — from classic manual code refactoring to complete redevelopment. But it wasn’t until I started working with Thinkwise that I realized a third path now exists: automated, model-based modernization that drastically reduces time, cost, and project risk.

Three Modernization Paths

Over the years, I’ve seen, analyzed, and evaluated hundreds of RPG systems. Based on this experience, I compared the three most common modernization approaches — with surprising results.

Note: The values below are estimates based on real-world project experience and are intended to illustrate typical ranges. Actual results may vary depending on system complexity and project scope.

The following overview shows the estimated effort for an RPG modernization using Thinkwise compared to alternative methods:

Even in the analysis phase, the advantage of automation and modelling becomes clear. While a manual migration requires the team to understand every program, variable, and interface individually and rebuild them from scratch, the Thinkwise RPG Upcycler automatically identifies the business logic and generates a modern application model — including relational data structures and user interfaces.

Cost Efficiency: Save 60–80% With Thinkwise

The financial impact is equally significant.

With Thinkwise, companies not only save money — they also drastically reduce their dependency on scarce RPG expertise. Rather than rewriting legacy code line by line, the existing logic is preserved and transferred into a future-proof, model-driven architecture. This is modernization at its most sustainable.

Quality & Future Readiness: Modern, Accurate, and Free from RPG Dependency

The key difference is this:
With Thinkwise, everything that matters is preserved: the knowledge, the processes, the logic. While the resulting application is fully modern, cloud-ready, and built on a sustainable architecture that self-documents and continuously evolves.

My Practical Conclusion

After decades in the IBM i world, I’m convinced:
Manual RPG modernization is no longer economically or technically justifiable.

With Thinkwise, companies can:

• Automatically migrate their business logic,

• Reduce time and cost by up to 80%,

• Eliminate their dependence on outdated RPG code.

The outcome is a modern, flexible application with no RPG dependency — one that keeps pace with business demands while minimizing project risk.

For any IBM i organization looking to modernize its core systems, the conclusion is clear:
Thinkwise isn’t just the faster path, it’s the more sustainable path into the future.

About the Author

Jürgen Schmidt, rsb-Schulung 
State-certified Business Economist (EDP), with more than 35 years of experience in the IBM i (formerly AS/400) ecosystem.

Jürgen began his career at IBM as a Systems Engineer and later spent many years as an IT and Project Manager. Since 1988, he has been working as a freelancer specializing in application development, database design, and training for IBM i systems.

As a professional freelancer with deep expertise in RPG, CL, system and database administration, he helps organizations optimize their IBM i environments efficiently and sustainably. Today, he provides consulting and training — both remotely and on-site — with a strong focus on practical applicability, technical precision, and tailored customer needs.