Rebooting Legacy Systems: Modernising COBOL Without Breaking Compliance

Fri, 30 May 2025 13:15:00 +0000

Somewhere in a bank right now, a COBOL program written before the person maintaining it was born is settling a payment. It has run every night for forty years, it has never been fully understood by anyone currently employed, and it processes a volume of money that makes the idea of “just rewriting it” the sort of joke that gets people fired. COBOL turns out to be one of the most quietly durable technologies ever built: code compiled in the 1970s still runs unmodified on IBM’s current z16 mainframe, because IBM has held backward compatibility across every hardware generation since. That durability is exactly the trap. The systems work, so no one touches them, so the knowledge of how they work leaks away one retirement at a time, until you are left with a black box that mints money and terrifies auditors.

Legacy-Systems - Tag - vo.rs

Rebooting Legacy Systems: Modernising COBOL Without Breaking Compliance