Mainframe modernization is often described as a move from older infrastructure to cloud platforms, modern databases, and more flexible architectures. But for Ankur Kalohia, a Pittsburgh-based technology leader and Director of Delivery Management at EPAM Systems, one of the hardest parts of modernization comes before migration begins: understanding what the legacy system actually does.

For modernization leaders, that missing understanding creates a business problem as much as a technical one. A company cannot confidently estimate migration cost, design a target-state architecture, or sequence transition waves if it does not understand the business rules and dependencies embedded in the current system. A missed rule can affect system behavior; a hidden dependency can delay a cutover; incomplete lineage can create downstream reporting or compliance risk.