I started work at a previous employer where the COBOL/ISAM system ran using DG COBOL and INFOS ISAM files for the data. It was already 12 years old when I started working for them. I worked there eleven years. It is now ten years later and that application is still running. While there we "integrated" it with SQL Server (downloads only) to provide enhanced reporting capabilities. That led the SQL Database to integrate with web based applications to create electronic delivery and print on demand capabilities. Then came a web based store that was built against Oracle but get its data from the SQL Server database. Another application was written that interfaced with both the SQL Server database and an Oracle database to allow for updates to the ISAM data tables used by the COBOL application.

Confused yet?

Just say, that COBOL application has its tentacles everywhere and will be difficult to replace, and several have tried and failed.