Rapid system understanding is required in the planning, feasibility assessment and cost estimating phases of a system renovation project. In this paper, we apply a number of analyses on two large legacy COBOL systems from the banking field. We describe the analyses performed, and discuss possible interpretations of these analyses. Lessons learned include: (1) The open architecture adopted is satisfactory, and can take advantage of a wide range of understanding tools available; and (2) To handle inter-system variability effectively, the flexibility of lexical analysis is required. 1991 Computing Reviews Classification System: D.2.2, D.2.7., D.3.4. Keywords and Phrases: Software visualization, lexical analysis, software reuse. Note: To appear in Proceedings of the 6th IEEE International Workshop on Program Comprehenson, June, 1998, Ischia.